Program and Abstracts

Oct.15 (Sun)

9:00
9:05
9:10
9:15
9:20
9:25
9:30
9:35
9:40
9:45
9:50
9:55
10:00
10:05
10:10
10:15
10:20
10:25
10:30
10:35
10:40
10:45
10:50
10:55
11:00
11:05
11:10
11:15
11:20
11:25
11:30
11:35
11:40
11:45
11:50
11:55
12:00
12:05
12:10
12:15
12:20
12:25
12:30
12:35
12:40
12:45
12:50
12:55
13:00
13:05
13:10
13:15
13:20
13:25
13:30
13:35
13:40
13:45
13:50
13:55
14:00
14:05
14:10
14:15
14:20
14:25
14:30
14:35
14:40
14:45
14:50
14:55 Wa Rasse 2F
15:00 Public lecture
15:05 (in Japanese)
15:10
15:15
15:20
15:25
15:30
15:35
15:40
15:45
15:50
15:55
16:00
16:05
16:10
16:15
16:20
16:25
16:30 Plasma Exhibition
16:35 (up to ~17:30)
16:40
16:45
16:50
16:55
17:00 Pre-registration
17:05 Wa Rasse 2F
17:10
17:15
17:20
17:25
17:30
17:35
17:40
17:45
17:50
17:55
18:00
18:05
18:10
18:15
18:20
18:25
18:30
18:35
18:40
18:45
18:50
18:55
19:00
19:05
19:10
19:15
19:20
19:25
19:30
19:35
19:40
19:45
19:50
19:55
20:00

Oct.16 (Mon)
Room A
Room B

Room CRoom D

Opening 15 min
PL-1 Plenary 30 min

PL-2 Plenary 30 min

Shih-Nan Hsiao

Jyh-Wei Lee(Green)Hiromasa Tanaka

Eun Ha Choi
(Bio)

Break 30 min Group photo|| 10 min|| 20 min
Hajime Sakakita
Hiroaki Nakamura
Yuzuro Ikehara
Kenji Ishikawa Kosuke Takenaka
PSLO-KN-1 25 min B-KN-1 25 min
S-I-1 20 min
WFPP-I-1 20 min
Minyou Ye
Shinya Toyokuni
Jaeho Kim
Giichiro Uchida
(PWI)
(Bio)
(Semi)(WFPP)
PSLO-KN-2 25 min
Guang-Hong Lu(PWI)
PSLO-KN-3 25 min
Shin Kajita(PWI)
PSLO-I-1 20 min
Yuan Yue(PWI)
Lunch 80 min|| 10 min|| 20 min|| 30 min|| 40 min|| 50 min|| 60 min|| 70 min

B-I-1 20 min
Ihn Han(Bio)
B-I-2 20 min
Bih-Show Lou(Bio)
B-I-3 20 min
Ying-Hung Chen
(Bio)
B-O-1 15 min
Camelia Miron(Bio)

S-KN-1 25 min
Shinjae You(Semi)
S-KN-2 25 min
Shu-Kai S Fan(Semi)
S-KN-3 25 min
Hisashi Yamada(Semi)WFPP-I-2 20 min

Munaswamy Murugesh(WFPP)WFPP-I-3 20 min
Shinjiro Ono(WFPP)WFPP-KN-1 40 min
Takeshi Kitajima(WFPP)

PL-3 Plenary (30 min)Jenq-Gong Duh(Green)Keigo Takeda

PL-4 Plenary (30 min)Haeyeop Chae
(Semicon)Jaeho Kim

Moving (10 min)Shin Kajita
Kotaro Yamasaki
Masahiro Shibuta
Takeshi Kitajima
PSLO-KN-4 25 min DX-I-1 20 min
GN-I-1 20 min
WFPP-I-4 20 min
Ivo Classen
Mi-Young Song
Hideaki Yamada
Yasuaki Hayashi
(SOL)
(DX)
(Green&nano)(WFPP)
PSLO-KN-5 25 min
Kyu-Sun Chung(SOL)

DX-I-2 20 min
GN-I-2 20 min
Ryohtaro Ishikawa Adnan Ali(DX)(Green&nano)

WFPP-I-5 20 min
Kazuo Takahashi(WFPP)

DX-I-3 20 min
Yoh-ichi Mototake(DX)

WFPP-I-6 20 min
Masaharu Shiratani(WFPP)

GN-I-3 20 min
Moo Been Chang(Green&nano)

Break 30 min|| 10 min|| 20 minIvo Classen
Yoh-ichi Mototake
Hideaki Yamada
Takeshi Kitajima
PSLO-KN-6 25 min DX-I-4 20 min
GN-I-4 20 min
WFPP-I-7 20 min
Hongbin Ding
Akira Kusaba
Avik Denra
JongYoon Park
(Laser)(DX)(Green&nano)(WFPP)
PSLO-I-2 20 min
Yong Sup Choi
(Laser)
PSLO-O-1 15 min
Jiaguan Peng
(PWI)
PSLO-O-2 15 min
Ze Chen(PWI)

DX-I-5 20 min
Keisuke Yano(DX)

GN-I-5 20 min
Sosiawati Teke
(Green&nano)

WFPP-I-8 20 min
Massimiliano Rome(WFPP)

DX-I-6 20 min
Pierre Vinchon(Semi)

GN-I-6 20 min
Masahiro Shibuta(Green&nano)

WFPP-I-9 20 min
Kosuke Takenaka(WFPP)

DX-I-7 20 min
Nikolay Britun(Laser)GN-I-7 20 min
Takashi Tsuji(Green&nano)

WFPP-I-10 20 min
Kazunori Koga
(WFPP)| Light meal (20 min)
WFPP-I-11 20 min|
Yasunori Tanaka| 10 minHiroki Kondo (WFPP)
Minyou Ye
Nikolay Britun
Takashi Tsuji
PSLO-O-3 15 min
DX-I-8 20 min
GN-KN-1 25 min
Hao YinMicheal K.T. Mo
Ju-Liang He(PWI)(Laser)(Green&nano)
PSLO-O-4 15 min
Yuto Toda
DX-O-1 15 min(PWI)
Fatima J Arellano
GN-I-8 20 min
Magdaleno
Oral 15 min(semi)
Vasquez Jr|
DX-O-2 15 min|
Sarah Alamri(Green&nano)
Oral 15 min(Semi)
GN-I-9 20 min|
DX-O-3 15 min
Jinjing LUO|
Pierre Mathieu(Green&nano)
Oral 15 min(Laser)|Oral 15 min
GN-O-1 15 min||
Mark Ilasin
Oral 15 min|(Green&nano)|
Oral 15 min
GN-O-2 15 min||
Liugang Hu
Oral 15 min|(Green&nano)|GN-O-3 15 min|
Quang Minh Ngo(Green&nano)Oct.17 (Tue)Oct.18 (Wed)

9:00
9:00 Room A
9:00
Room B
Room CRoom D
9:05
9:05
9:05
9:10
9:10
9:10 Poster 150 min
9:15 PL-5 Plenary (30 min)Kazunori Koga 9:15
9:15
9:20
9:20
Christian Petrica Lungu
9:20
9:25
9:25
9:25
9:30
9:30
9:30
9:35
9:35
9:35
9:40
9:40
9:40
9:45
9:45 PL-6 Plenary (30 min)Camelia Miron 9:45
9:50
9:50
Juergen F. Kolb
9:50
9:55
9:55
(Bio)
9:55
10:00
10:00
10:00
10:05
10:05
10:05
10:10
10:10
10:10
10:15 Break 30 min
10:15
10:15
10:20
10:20 |
10:20
10:25
10:25 | 10 min
10:25
10:30 (Break 30 min)
10:30 |
10:30
10:35
10:35 | 20 min
Kenji Ishikawa 10:35
10:40
10:40
Kyu-Sun Chung
Inh Han Takashi Nishizawa
Keigo Takeda 10:40
10:45
10:45 PSLO-I-3 20 min
B-KN-2 25 min
DX-KN-1 25 min
S-KN-4 25 min
10:45
10:50
10:50 Long Cheng
Yuzuru Ikehara
Young-chul Ghim
Geun Young Yeom 10:50
10:55
10:55 (PWI)
(Bio)
(DX)
(Semicon)
10:55
11:00
11:00
11:00
11:05
11:05 PSLO-I-4 20 min
11:05
11:10
11:10 Dogyun Hwangbo B-KN-3 25 min
DX-I-9 20 min
S-KN-5 25 min
11:10
Fumikazu
11:15
11:15 (PWI)
Mudtorlep Nisoa
Sang Hoon Ahn
11:15
Miwakeichi (DX)
11:20
11:20
(Bio)
(Semicon)
11:20
11:25
11:25 PSLO-I-5 20 min
11:25
11:30
11:30 Yuki Hayashi
DX-I-10 20 min
11:30
11:35
11:35 (SOL)
B-I-4 20 min
Kotaro Yamasaki
S-I-2 20 min
11:35
11:40 Lunch 80 min
11:40
Yun Chien Cheng (DX)
Satoshi Hamaguchi 11:40
11:45 |
11:45 PSLO-I-6 20 min(Bio)(Semi)
11:45
11:50 Hirohiko Tanaka
DX-I-11 20 min
11:50
11:50 | 10 min
11:55 (SOL)
B-I-5 20 min
Yuichi Kawachi
GN-I-10 20 min
11:55
11:55 |
Ghayas Uddin
12:00 | 20 min
12:00
Jun Sup Lim
(DX)
12:00
Siddiqui
12:05 |
12:05 PSLO-I-7 20 min
(Bio)
12:05
12:10 | 30 min
12:10 Satoshi Togo
DX-I-12 20 min(Green&nano)
12:10
12:15 |
12:15 (SOL)
Takuma Yamada
GN-I-11 20 min
12:15
12:20 | 40 min
12:20
(DX)
Mineo Hiramatsu
12:20
12:25 |
12:25 Lunch 60 min(Green&nano)
12:25
12:30 |
12:30
12:30 | 50 min
12:35 | 10 min
12:35
12:35 |
12:40 |
12:40
12:40 | 60 min
12:45 |
12:45 | 20 min
12:45
12:50 | 70 min
12:50 |
12:50
12:55 |
12:55 | 30 min
12:55
13:00 Assembly
13:00 |
13:00
13:05 |
13:05 | 40 min
13:05
13:10 Bus departure
13:10 |
13:10
13:15 | 50 min
13:15
13:15 to13:20 Sannai-Maruyama 13:20
13:20
13:25 Site
13:25 PL-7 Plenary (30 min)
Kenji Ishikawa 13:25
13:30
13:30
Masahiro Horibe
13:30
13:35
13:35
(DX)
13:35
13:40
13:40
13:40
13:45
13:45
13:45
13:50
13:50
13:50
13:55
13:55 PL-8 Plenary (30 min)Noriyasu Ohno 13:55
14:00
14:00
D. Reiter
14:00
14:05
14:05
(SOL)
14:05
14:10
14:10
14:10
14:15
14:15
14:15
14:20
14:20
14:20
14:25
14:25
Atsushi Ito
HiromasaTanaka
Takuma Yamada
Mineo Hiramatsu 14:25
14:30
14:30 PSLO-I-8 20 min
B-I-6 20 min
DX-I-13 20 min
GN-I-12 20 min
14:30
14:35
14:35
14:35 Hiroaki Nakamura Mohandas Roopesh Takashi Nishizawa Wei-Cheng Lin
14:40
14:40 (Optics)
(Bio)
(DX)
(Green&nano)
14:40
14:45
14:45
14:45
14:50
14:50 PSLO-I-9 20 min
B-I-7 20 min
DX-I-14 20 min
GN-I-13 20 min
14:50
14:55
14:55 Yoshihisa Fujita
Hiromasa Yamada Eiichirou Kawamori ChinWook Chung 14:55
15:00
15:00 (Optics)
(Bio)
(DX)
(Green&nano)
15:00
15:05
15:05
15:05
GN-I-14 20 min
15:10
15:10
15:10 PSLO-I-10 20 min B-I-8 20 min
DX-I-15 20 min
Katsuyuki Takahash Shih-Nan Hsiao
Ping-Yen Hsieh
15:15
15:15
15:15 Quan Shi
15:20
15:20 (Optics)(Bio)(Semi)(Green&nano)
15:20
15:25
15:25
15:25
15:30
15:30 Closing award celemony (30 min)
15:30
15:35
15:35 |
15:35
15:40
15:40 | 10 min
15:40
15:45
15:45 |
15:45
15:50
15:50 | 20 min
15:50
15:55
15:55 |
15:55
16:00
16:00
16:00
16:05
16:05
16:05
16:10
16:10
16:10
16:15
16:15
16:15
16:20
16:20
16:20
PSLO: PWI/SOL/Laser/Optics
16:25
16:25
16:25
16:30
16:30
16:30
DX: Data-driven
16:35
16:35
16:35
B：
Bio
16:40
16:40
16:40
S：
Semiconductor
16:45 Assembly
16:45
16:45
GN： Green & nano
16:50
16:50
16:50
16:55
16:55
16:55
WFPP: Workshop on Fine Particles Physics (jointly held)
17:00 Bus departure
17:00
17:00
17:05 to Wa Rasse
17:05
17:05
17:10
17:10
17:10
Chairs in red
17:15
17:15
17:15
17:20
17:20
17:20
17:25
17:25
17:25
17:30 Banquet 120 min 17:30
17:30
17:35
17:35
17:35
17:40
Wa Rasse 1F
17:40
17:40
17:45
17:45
17:45
17:50
17:50
17:50
17:55
17:55
17:55
18:00
18:00
18:00
18:05
18:05
18:05
18:10
18:10
18:10
18:15
18:15
18:15
18:20
18:20
18:20
18:25
18:25
18:25
18:30
18:30
18:30
18:35
18:35
18:35
18:40
18:40
18:40
18:45
18:45
18:45
18:50
18:50
18:50
18:55
18:55
18:55
19:00
19:00
19:00
19:05
19:05
19:05
19:10
19:10
19:10
19:15
19:15
19:15
19:20
19:20
19:20
19:25
19:25
19:25
19:30
19:30
19:30
19:35
19:35
19:35
19:40
19:40
19:40
19:45
19:45
19:45
19:50
19:50
19:50
19:55
19:55
19:55
20:00
20:00
20:00

GPF-Aomori Program

In the order of Day, Room, Time

Poster List from p.10

Oct. 16 (Mon)
Room A
9:15-9:30 Opening Ceremony
Room A
9:30-10:00 PL-1 Jyh-Wei Lee (Ming Chi University of Technology, Taiwan)
Current research of cold atmospheric plasma and plasma-based thin film technologies in CPTFT, MCUT,
Taiwan
10:00-10:30 PL-2 Eun Ha Choi (Kwangwoon University, Republic of Korea)
Plasma Agriculture Works with Plasma Treated Nitric Oxide Water (PTNOW) in Korea

Group Photo (Place will be announced)
Coffee Break (2F)
Room A
11:00-11:25 PSLO-KN-1 Minyou Ye (University of Science and Technology of China, China)
Hydrogen isotope behavior in tungsten and RAFM steels
11:25-11:50 PSLO-KN-2 Guang-Hong Lu (Beihang University, China)
Beneficial Effects of Helium in Tungsten in Context of Fusion Plasma and Wall Interactions
11:50-12:15 PSLO-KN-3 Shin Kajita (The University of Tokyo, Japan)
Effect of co-deposition on helium plasma irradiation to tungsten
12:15-12:35 PSLO-I-1 Yue Yuan (Beihang University, China)
Performance of tungsten materials under sequential high heat flux loading and deuterium plasma exposure

Room B
11:00-11:25 B-KN-1 Shinaya Toyokuni (Nagoya University, Japan)
Low-temperature plasma as a ferroptosis inducer in cancer cells
11:25-11:45 B-I-1 Ihn Han (Kwangwoon University, Republic of Korea)
Assessment of probability estimation on human tissue-derived fibroblast/stromal cells response to nonthermal biocompatible plasma
11:45-12:05 B-I-2 Bih-Show Lou (Chang Gung University, Taiwan)
Cold atmospheric plasma facilitates wound healing for type 2 diabetes and skin flap treatments1

12:05-12:25 B-I-3 Ying-Hung Chen (Feng Chia University, Taiwan)
In vivo toxicity test of DBD plasma activated water by using Zebrafish
12:25-12:40 B-O-1 Camelia Miron (Nagoya University, Japan)
Chemically active compounds formed in low-temperature plasma treated liquids for cancer treatment

Room C
11:00-11:20 S-I-1 Jaeho Kim (Samsung Electronics, Republic of Korea)
Recent trends of plasma deposition technologies for the development of next-generation electronic devices
11:20-11:45 S-KN-1 Shinjae You (Chungnam National University, Republic of Korea)
On the mechanism of Arcing phenomenon in low temperature plasma
11:45-12:10 S-KN-2 Shu-Kai S. Fan (National Taipei University of Technology, Taiwan)
Enterprise intelligentization of semiconductor manufacturing in Taiwan
12:10-12:35 S-KN-3 Hisashi Yamada (National Institute of Advanced Industrial Science andTechnology, Japan) Ammonia-free plasma-enhanced MOCVD for nitride semiconductors

Room D - Workshop on Fine Particle Plasma 10:00-10:20 WFPP-I-1 Giichiro Uchida (Meijo University, Japan)
Property control of Ge and Si nanostructured films by high-pressure He sputtering process for nextgeneration Li ion battery
10:20-10:40 WFPP-I-2 Munaswamy Murugesh (Hokkaido University, Japan)
A process for synthesizing melted tin-carbon core-shell nanoparticles using dusty plasma
10:40-11:00 WFPP-I-3 Shinjiro Ono (Kyushu University)
Controlling the synthesis, transport, and surface coverage of carbon nanoparticles using plasma CVD
11:00-11:40 WFPP-KN-1Takeshi Kitajima (National Defense Academy of Japan, Japan)
Plasmonic plasma process using nanoparticles on substrate

Lunch BreakRoom A
14:00-14:30 PL-3 Jenq-Gong Duh (National Tsing-Hua University, Taiwan)
Exploration of atmospheric pressure plasma technique in the surface modification on anode material forhigh-rate lithium-ion battery and rapid organic fertilizer manufacturing for sustainable farming
14:30-15:00 PL-4 Heeyeop Chae (Sungkyunkwan University, Republic of Korea)
2

Plasma-enhanced atomic layer etching for metals and dielectric materials

Room A
15:10-15:35 PSLO-KN-4 Ivo Classen (Dutch Institute For Fundamental Energy Research, The
Netherlands) Overview of plasma heat exhaust studies in the DIFFER linear devices
15:35-16:00 PSLO-KN 5 Kyu-Sun Chung (Hanyang University, Republic of Korea)
Review on DiPS-2 as a linear plasma device: source, diagnostics, physics and PMI

Room B
15:10-15:30 DX-I-1 Mi-Young Song (Korea Institute of Fusion Energy, Republic of Korea)
Plasma fundamental research activities based on atomic and molecular data in Korea institute of fusionenergy15:30-15:50 DX-I-2 Ryohtaro T. Ishikawa (National Institute for Fusion Science, Japan)
Multi-scale deep learning for estimating horizontal velocity fields on the solar surface
15:50-16:10 DX-I-3 Yoh-ichi Mototake (Hitotsubashi University, Japan)
Interpretable AI supporting scientists' insight into large-scale dynamics

Room C
15:10-15:30 GN-I-1 Hideaki Yamada (National Institute of Advance Industrial Science andTechnology, Japan) Plasma processing for diamond wafers
15:30-15:50 GN-I-2 Adnan Ali (Jeju National University, Republic of Korea)
Nitrogen doped and undoped Ti3C2Tx/Co3O4 hybrid composites synthesis for application as anodematerials in flexible Supercapacitor
15:50-16:10 GN-I-3 Moo Been Chang (National Central University, Taiwan)
Development of plasma catalysis system for reducing the emissions of GHGs and air pollutants

Room D - Workshop on Fine Particle Plasma 15:10-15:30 WFPP-I-4 Yasuaki Hayashi (Yamato University, Japan)
Gradient-descent-method analysis of Mie-scattering ellipsometry during fine-particle growth in plasma
15:30-15:50 WFPP-I-5 Kazuo Takahashi (Kyoto Institute of Technology, Japan)
Analyses of Coulomb crystals in dusty plasmas under gravity and microgravity
15:50-16:10 WFPP-I-6 Masaharu Shiratani (Kyushu University, Japan)
Highly sensitive electric field vector measurements using an optically trapped fine particle

Coffee Break (2F)
3

Room A
16:40-17:05 PSLO-KN-6 Hongbin Ding (Dalian University of Technology, China)
Laser-induced breakdown spectroscopy for wall diagnosis in nuclear fusion devices
17:05-17:25 PSLO-I-2 Yong Sup Choi (Korea Institute of Fusion Energy, Korea)
Development of plasma application technology in IPT-KFE
17:25-17:40 PSLO-O-1 Jia-Guan Peng (Beihang University, China)
Surface morphology and grain structure changes induced by helium ion implantation and subsequent
thermal annealing
17:40-17:55 PSLO-O-2 Ze Chen (University of Science and Technology of China, China)
MD simulation of the interaction between hydrogen and helium bubble in bcc iron

Room B
16:40-17:00 DX-I-4 Akira Kusaba (Kyushu University, Japan)
Data assimilation in semiconductor crystal growth: chemical reaction network modeling
17:00-17:20 DX-I-5 Keisuke Yano (The Institute of Statistical Mathematics, Japan)
A new approach to mixed-domain and higher-order dependence modeling
17:20-17:40 DX-I-6 Pierre Vinchon (Osaka University, Japan)
Monolayer Graphene, an ideal material for exploring out-of-equilibrium phenomena involved in plasmasurface interactions
17:40-18:00 DX-I-7 Nikolay Britun (Nagoya University, Japan)
Poly-diagnostics of a nanosecond He-based atmospheric plasma

Room C
16:40-17:00 GN-I-4 Avik Denra (Jeju National University, Republic of Korea)
Application of gliding arc plasma in nitrogen fixation: conversion of atmospheric nitrogen into nitro
compounds
17:00-17:20 GN-I-5 Sosiawati Teke (Jeju National University, Republic of Korea)
The potential of a simple microplasma reactor in cobalt oxide nanoparticle synthesis
17:20-17:40 GN-I-6 Masahiro Shibuta (Osaka Metropolitan University, Japan)
Sputter-grown size-selected nanocluster synthesis: deposition and characterization for material science
17:40-18:00 GN-I-7 Takashi Tsuji (National Institute of Advanced Industrial Science and Technology,
Japan) A microplasma-based approach for the growth of highly crystalline carbon nanotubes
4

Room D - Workshop on Fine Particle Plasma 16:40-17:00 WFPP-I-7 JongYoon Park (Seoul National University, Republic of Korea)
Discharge mode transition triggered by three-wave coupling in partially magnetized cross-field plasma
17:00-17:20 WFPP-I-8 Massimiliano Romé (University of Milano, and INFN-Milano, Italy)
Non-neutral plasmas in Penning-Malmberg traps: fundamental studies and applications
17:20-17:40 WFPP-I-9 Kosuke Takenaka (Osaka University, Japan)
Plasma-assisted mist CVD for formation of 3D nanostructured zinc oxide thin films
17:40-18:00 WFPP-I-10 Kazunori Koga (Kyushu University)
Evaluation of carbon nanoparticle adhesion on substrate surface deposited by plasma CVD
18:00-18:20 WFPP-I-11 Yasunori Tanaka (Kanazawa University)
Contribution of Condensation and Coagulation for Nanoparticle Growth in Modulated Induction Thermal
PlasmasLight Meal (Coffee Break Place)
Room A
18:20-18:35 PSLO-O-3 Hao Yin (Beihang University, China)
Surface blistering and deuterium retention in chemical vapor deposition tungsten exposed to deuterium
plasma18:35-18:50 PSLO-O-4 Yuto Toda (SOKENDAI, Japan)
Time-dependent density functional theory simulation for neutralization process of hydrogen ion injected
onto graphene

Room B
18:20-18:40 DX-I-8 Micheal Mo (Nagoya University, Japan)
Simultaneous measurements of F, O and H ground state atom density in an industry-grade etching plasma
18:40-18:55 DX-O-1 Fatima Jenina Arellano (Osaka University, Japan)
Machine learning prediction of plasma parameters from optical emission spectra in argon plasma
18:55-19:10 DX-O-2 Sarah S. N. Alamri (Osaka University, Japan)
Numerical simulation of RF-driven capacitively coupled argon plasmas and comparison with experimental
observations
19:10-19:25 DX-O-3 Pierre Mathieu (University of Mons, Belgium)
Preliminary investigation of methane plasmalysis in an atmospheric pressure gliding arc plasma
5Room C
18:20-18:45 GN-KN-1 Ju-Liang He (Feng Chia University, Taiwan)
Broadening plasma polymerization process for functional coatings
18:45-19:05 GN-I-8 Magdaleno R Vasquez Jr. (University of the Philippines Diliman, Philippines)
Development of atmospheric pressure plasma sources for material modification
19:05-19:25 GN-I-9 Jinjing Luo (Xiamen University, China)
Surface modification by non-thermal plasma for gaseous mercury removal
19:25-19:40 GN-O-1 Mark D. Ilasin (University of the Philippines Diliman, Philippines)
Amorphous carbon film deposition using low-energy ions
19:40-19:55 GN-O-2 Liugang Hu (Nagoya University, Japan)
Selective removal of graphene by irradiation of remote oxygen plasma
19:55-20:10 GN-O-3 Ngo Quang Minh (Nagoya University, Japan)
Synthesis and characteristics of carbon nanowalls using two-step growth combining different plasma
chemical vapor deposition methods

Oct. 17 (Tue)9:10~11:40 Poster Session (Room B+C+D), “poster list” at the end of this program
13:00 Assembly at Coffee Break Place
13:10 Bus departure for Sannai-Maruyama Site
16:45 Assembly at Sannai-Maruyama Site Entrance
17:00 Bus departure for Wa Rasse
17:30 “Feel and Enjoy Aomori” Banquet at Wa Rasse

Oct. 18 (Wed)Room A
9:15-9:45 PL-5 Cristian Petrica Lungu (National Institute for Laser, Plasma and Radiation Physics,
Romania) Beryllium dust preparation to mimic particle formation in fusion devices
9:45-10:15 PL-6 Juergen F. Kolb (Leibniz Institute for Plasma Science and Technology, Germany)
6Plasma treatment of water for agricultural production

Coffee Break (2F)
Room A
10:45-11:05 PSLO-I-3 Long Cheng (Beihang University, China)
Mechanism of blistering and retention in recrystallized tungsten exposed to deuterium plasma in the linear
plasma device STEP
11:05-11:25 PSLO-I-4 Dogyun Hwangbo (University of Tsukuba, Japan)
Spectroscopic measurement of deuterium recycling at molybdenum surfaces
11:25-11:45 PSLO-I-5 Yuki Hayashi (National Institute for Fusion Science, Japan)
Study on effects of neutral particle behavior on detached plasma formation using linear plasma device andmodeling
11:45-12:05 PSLO-I-6 Hirohiko Tanaka (Nagoya University, Japan)
Newly developed integrated transport code for detached plasma simulation
12:05-12:25 PSLO-I-7 Satoshi Togo (The University of Tsukuba, Japan)
Development of a plasma fluid model covering a range of coulomb collisionality by comparison with aparticle-in-cell model

Room B
10:45-11:10 B-KN-2 Yuzuru Ikehara (Chiba University, Japan)
The feasibility of using ions and charges in the medical field
11:10-11:35 B-KN-3 Mudtorlep Nisoa (Walailak University, Thailand)
Low-temperature and thermal plasma research at PEwave, Walailak University
11:35-11:55 B-I-4 Yun-Chien Cheng (National Yang Ming Chiao Tung University, Taiwan)
Atmospheric-pressure plasma effects on cancer cells and RONS generation for medical applications
11:55-12:15 B-I-5 Jun Sup Lim (Kwangwoon University, Republic of Korea)
Effect of accumulated charge on the dynamics of plasma bullet propagation

Room C
10:45-11:10 DX-KN-1 Young-Chul Ghim (Korea Advanced Institute of Science and Technology,
Republic of Korea) Ion flux reduction factor at the sheath edge as a function of ion-neutral collisions in low
temperature Ar or He DC plasmas
11:10-11:30 DX-I-9 Fumikazu Miwakeichi (The Institute of Statistical Mathematics, Japan)
7Quantification of causality among frequency modes in linear plasma using vector autoregressive models
11:30-11:50 DX-I-10 Kotaro Yamasaki (Hiroshima University, Japan)
Basis function analysis technique for the two-dimensional structure of fluctuation in magnetized plasma
11:50-12:10 DX-I-11 Yuichi Kawachi (Kyoto Institute of Technology, Japan)
Applications of conditional sampling technique to time series of experimental plasma data
12:10-12:30 DX-I-12 Takuma Yamada (Kyushu University, Japan)
Multiple correlation analysis of nonlinear dynamics in plasma turbulence

Room D
10:45-11:10 S-KN-4 Geun Young Yeom (Sungkyunkwan University, Republic of Korea)
Beam-assisted atomic layer etching
11:10-11:35 S-KN-5 Sang Hoon Ahn (Samsung Electronics Co. Ltd., Republic of Korea)
Past, present, and future plasma solutions to semiconductor challenges
11:35-11:55 S-I-2 Satoshi Hamaguchi (Osaka University, Japan)
Plasma-enhanced atomic layer processing for semiconductor processing
11:55-12:15 GN-I-10 Ghayas Uddin Siddiqui (Jeju National University, Republic of Korea)
Adsorptive removal of cationic and anionic dyes using nanocomposite of graphene oxide/zinc oxide fromaquatic environment
12:15-12:35 GN-I-11 Mineo Hiramatsu (Meijo University, Japan)
3D-graphene networks: synthesis and applications

Lunch BreakRoom A
13:25-13:55 PL-7 Masahiro Horibe (National Institute of Advanced Industrial Science andTechnology, Japan) Near-future industrial innovation Digital transformation (DX) to Quantum
transformation (QX)
13:55-14:25 PL-8 Detlev Reiter (Heinrich-Heine-Universität Düsseldorf, Germany)
Divertor detachment: Fusion plasma physics meets plasma chemistry

Room A
14:30-14:50 PSLO-I-8 Hiroaki Nakamura (National Institute for Fusion Science, Japan)
Verification of birth process of primordial organic molecules in the solar system from molecular clouds using
molecular dynamics simulations8

14:50-15:10 PSLO-I-9 Yoshihisa Fujita (Nihon University, Japan)
Angular momentum coupling of tilted gaussian beam with waveguide mode
15:10-15:30 PSLO-I-10 Quan Shi (The University of Tokyo, Japan)
A simple method for modifying the surface morphology of various semiconductors and its application in
random lasing

Room B
14:30-14:50 B-I-6 Roopesh Mohandas Syamaladevi (M. S. Roopesh) (University of Alberta, Canada)
Applications of cold plasma technology in the agri-food industry
14:50-15:10 B-I-7 Hiromasa Yamada (National Institute Technology, Nagano College, Japan)
Behavior of gas flow and characteristics of atmospheric pressure plasma jet for bio-applications
15:10-15:30 B-I-8 Katsuyuki Takahashi (Iwate University, Japan)
Environmental control for plant growth and preservation using high-voltage pulsed discharges

Room C
14:30-14:50 DX-I-13 Takashi Nishizawa (Kyushu University, Japan)
Simultaneous inference of multiple plasma parameter profiles by utilizing transport properties
14:50-15:10 DX-I-14 Eiichirou Kawamori (National Cheng Kung University, Taiwan)
Information thermodynamics of plasma wave turbulence
15:10-15:30 DX-I-15 Shih-Nan Hsiao (Nagoya University, Japan)
On the mechanism of high-speed SiO2 etching using hydrogen fluoride-contained plasmas at cryogenic
temperature

Room D
14:30-14:50 GN-I-12 Wei-Cheng Lin (Ming Chi University of Technology, Taiwan)
Feasibility of applying non-thermal plasma to the degradation of pharmaceuticals in real medical
wastewater
14:50-15:10 GN-I-13 ChinWook Chung (Hanyang University, Republic of Korea)
Novel plasma source for atomic scale processing
15:10-15:30 GN-I-14 Ping-Yen Hsieh (Feng Chia University, Taiwan)
Yttrium-based plasma etching resistant coating obtained by gas flow sputter deposition

Room A9

15:30-16:00 Closing, Award Ceremony
Adjourn

Poster Presentation List
Oct. 17 (Tue) 9:10~11:40 Room B+C+D
P-1 Young-Gi Kim (Korea Institute of Fusion Energy, Republic of Korea)
Design of a Thomson scattering system for atmospheric plasma sources
P-2 Masayuki Tokitani (National Institute for Fusion Science, Japan)
Irradiation experiment of new type of divertor heat removal component fabricated by AMSB to LHD divertor
plasmaP-3 Yuki Goto (National Institute for Fusion Science, Japan)
Theoretical issue of the electron cyclotron emission with decay process in a waveguideP-4 Mamoru Shoji (National Institute for Fusion Science, Japan)
Simulation analysis of lithium transport in the peripheral plasma during impurity powder injection in the
Large Helical Device
P-5 Sotaro Tsuru (Nagoya University, Japan)
Molecular dynamics simulation for elucidation of vacancy coalescence in tungsten crystal
P-6 Zhe Liu (University of Science and Technology of China, China)
Nanopatterning of Si by low-energy He plasma irradiation
P-7 Rongshi Zhang (Nagoya University, Japan)
Growth of micro-pillars on tungsten by helium plasma exposure with impurity gases
P-8 Long Li (University of Science and Technology of China, China)
Surface modification of ZrC dispersion-strengthened W under low energy He plasma irradiation
P-9 Ryutaro Kanno (National Institute for Fusion Science, Japan)
Probabilistic modeling of impurity transport based on the drift-kinetic equation
P-10 Naonori Okada (Tokai University, Japan)
2-D spectroscopic measurement of Balmer series in detached plasma with ICR heating
P-11 Keigo Yoshimura (Tohoku University, Japan)
Analysis of molecular activated recombination in hydrogen plasma produced in radio-frequency plasma
10source DT-ALPHA
P-12 Arimichi Takayama (National Institute for Fusion Science, Japan)
Diffusion Behavior of Adatom on Tungsten Surface Evaluated by Density Functional Theory Calculation
P-13 Gakushi Kawamura (National Institute for Fusion Science, Japan)
Weighted sum estimation of radiation power and toroidal asymmetry in LHD
P-14 Hiroyuki Takahashi (Tohoku University, Japan)
Evaluation of proton density ratio in a bucket-type ion source based on
kinetic code plasma simulation and rate equation for hydrogen ionsP-15 Mitsuo Tajima (University of Hyogo, Japan)
Formation of fiber-form nanostructures and He bubbles/holes on tungsten surfaces by collisional helium arc
plasma irradiation
P-16 Atsushi Ito (National Institute for Fusion Science, Japan)
Simulation development for the next stage of plasma-material interaction
P-17 Ryusei Koyama (Nihon University, Japan)
Visualization of metastable helium distribution using ghost imaging absorption spectroscopy
P-18 Hideki Kawaguchi (Muroran Institute of Technology, Japan)
Analysis of scattering of UV vortex from helix conductor using MoM
P-19 Wang Chenxu (Muroran Institute of Technology, Japan)
Evaluation of propagation of millimeter wave vortex using FDTD method
P-20 Yuta Uematsu (Nagoya University, Japan)
Observation of global structural changes in two-dimensional emission profiles associated with attached anddetached plasma transitions
P-21 Masanori Yamamoto (Nagoya University, Japan)
Formation of helium-tungsten co-deposition layers and spectroscopic measurements during sputtering
P-22 Kazuma Emoto (University of Tsukuba, Japan)
A preliminary kinetic study on plasma flow in open magnetic systems using a quasi-one-dimensional
particle-in-cell model
P-23 Kiho Tabata (Nagoya University, Japan)
Porous silicon produced with helium plasma for lithium-ion battery anode11

P-24 Masahiro Katoh (Hiroshima University, Japan)
Phase structure and angular momentum of cyclotron radiation
P-25 Kazutaka Onoda (University of Tsukuba, Japan)
Spectroscopic measurement of microwave atmospheric pressure nitrogen plasma and the effect of vapor
addition on the hydrophilicity of polystyrene surface
P-26 Kaito Miura (Tokai University, Japan)
Effect of argon additive in Cs-free negative hydrogen ion source
P-27 Ryo Sasaki (University of Tsukuba, Japan)
Correlation of tungsten surface morphology changes and deuterium absorption properties by deuterium
plasma exposure with pulsed heat load
P-28 Kota Saito (University of Tsukuba, Japan)
The appearance of deuterium low temperature desorption at modified tungsten surfaces under helium preexposure conditions
P-29 Takuma Okamoto (University of Tsukuba, Japan)
Investigation of reaction process during combined seeding of nitrogen and hydrogen in divertor simulated
plasmaP-30 Toseo Moritaka (National Institute for Fusion Science, Japan)
Electrostatic field calculation on a curved surface for gyrokinetic modeling of stellarator edge plasmas
P-31 Joseph Xinze Li (SOKENDAI, Japan)
Development of a kinetic transport model in broken flux surfaces
P-32 Yoshihide Shibata (National Institute of Technology, Gifu College, Japan)
Example of medical and engineering collaboration in data analysis in the field of the nuclear fusion
P-33 Kouta Ishigure (Meijo University, Japan)
Synthesis of graphitic carbon nitride on carbon nanowalls
P-34 Kodai Ishikawa (Meijo University, Japan)
Nitrogen addition to diamond using radical injection-CVD
P-35 Zhe-Wei Gong (Ming Chi University of Technology, Taiwan)
Defluorinated degradation of per/poly fluoro alkyl substances (PFAS) in water using non-thermal plasma
P-36 Jumma Kagami (Meijo University, Japan)
Immobilization of glucose oxidase on carbon nanowalls
12P-37 Yukei Ishihara (University of Tsukuba, Japan)
Protein aggregation driven by atmospheric pressure plasma between needle electrode and surface ofalbumin solution
P-38 Mitsutaka Isobe (National Institute for Fusion Science, Japan)
Advances in development of quasi-axisymmetric stellarator at National Institute for Fusion Science
P-39 Yuto Yanagihara (National Institute for Fusion Science, Japan)
Low-temperature sintering of activated carbon using spark plasma sintering
P-40 Kazuki Nagahara (National Institute for Fusion Science, Japan)
Enhancement to gas puffing control system in LHD
P-41 Sho Nakagawa (National Institute for Fusion Science, Japan)
Surface observation on heat-treated activated carbon derived from unutilized biomass
P-42 Yang Ming (Nagoya University, Japan)
Ferroptosis induced by plasma-activated Ringer’s lactate solution prevents oral cancer progression
P-43 Kae Nakamura (Nagoya University, Japan)
Plasma-activated solutions invigorate anti-tumor immune response in the intraperitoneal environments ofovarian cancer
P-44 Chih-Yu Ma (Louis Pasteur Center for Medical Research, Taiwan)
Prevalence of antibiotic-resistant E. coli in wastewater treatment plant effluent and the southern watershedof Lake Biwa
P-45 Dhammanoon Srinoum (Walailak University, Thailand)
Production of large volume plasma-activated water (PAW) for food and agricultural applications
P-46 Suttirak Kaewpawong (Walailak University, Thailand)
Development of 10 kW helicon plasma source for material-plasma interaction studies
P-47 Ridvee Taleh (Walailak University, Thailand)
Characteristics of high-power DC thermal plasmas for treatment of medical wastes
P-48 Akihiro Kajino (Meijo University, Japan)
Atmospheric pressure hybrid plasma jet for oxygen atom generation
P-49 In Je Kang (Korea Institute of Fusion Energy, Republic of Korea)
Analysis of plasma flow velocity in highly collisional plasma jet by using Mach probe for plasma aerosol
13

deposition
P-50 Hyunyeong Lee (Korea Institute of Fusion Energy, Republic of Korea)
Design on versatile large area PECVD system for the assessment of plasma property
P-51 Jong Woo Hong (Sungkyunkwan University, Republic of Korea)
Etch characteristics of ITO using various hydrofluorocarbon gases
P-52 Hyun Woo Tak (Sungkyunkwan University, Republic of Korea)
Etching characteristics of SiON films with a low global warming potential gas replacing CF4
P-53 Hiroharu Kawasaki (National Institute of Technology, Sasebo College, Japan)
Dependence of the film qualities on the solied densities of the targets prepared by sputtering deposition
with mixture powder targets
P-54 Masayuki Yokoyama (National Institute for Fusion Science, Japan)
Introduction to IAEA coordinated research program (CRP): AI for Fusion (AI4F)“Meet the Aomori” (in Japanese)
青森県産業技術センター様からのポスター展示：５件予定（内訳：予定）本部企画経営室＋工業、農林、水産、食品加工の４部門
（募集中）

14

October 16（Monday）

PL-1

Current research of cold atmospheric plasma and plasma-based thin film
technologies in CPTFT, MCUT, Taiwan
1

Jyh-Wei Lee1,2,3*, Chi-Lung Chang1,2, Li-Chun Chang1,2, Jang-Hsing Hsieh1,2

Department of Materials Engineering, Ming Chi University of Technology, New Taipei, Taiwan,
Center for Plasma and Thin Film Technologies, Ming Chi University of Technology, New Taipei, Taiwan
3
Department of Mechanical Engineering, Chang Gung University, Taoyuan, Taiwan
E-mail: jefflee@mail.mcut.edu.tw
2

The Center for Plasma and Thin Film Technologies (CPTFT) at Ming Chi University ofTechnology (MCUT), Taiwan, was established in December 2010. CPTFT is designed todevelop and promote advanced plasma and thin film technologies. In CPTFT, there are fiveresearch groups: biomedical thin films, energy-related thin films, HiPIMS technologies,
optoelectronic and semiconductor thin films, and plasma technologies. Currently, we focus on
the research and application of cold atmospheric plasma techniques and plasma-based thin film
fabrications. In the research of cold atmospheric plasma, the biomedical applications in theantimicrobial, wound healing, and skin flap treatment have been studied extensively. The
sewage treatment by cold atmospheric plasma technique became an important cooperation
project with Prof. Wen-Hui Kuan in MCUT. Recently, we started to promote the unique power
supply for cold atmospheric plasma systems, pet animal wound healing treatment systems, andthe plasma-activated water machine.
Plasma-based thin film fabrication methods have been widely used in academia andindustries due to their flexibility and enabling the growth of many functional coatings. Among
many plasma-based thin film deposition methods, the high power impulse magnetron sputtering(HiPIMS) technique is characterized by its ability to fabricate functional thin films with dense
microstructure and better film quality. Currently, CPTFT has the largest research group andfacilities in the research and development of HiPIMS technology. Some successful HiPIMS
research results have been transferred to industries, including anti-sticking coatings on
microdrills, embossing dies, and plastic injection molds. The design and manufacturing of the
HiPIMS-Arc hybrid deposition system was also a successful product in CPTFT. The researchof thin film metallic glasses and high entropy alloy thin films applied in the biomedical fields
is highlighted in CPTFT. Researching semiconductor thin films fabricated by atomic layer
deposition systems is also an important topic. In this presentation, we will present some We arewilling to collaborate with academia and industries worldwide in every aspect of plasma
technology and thin film technology.
[1] B.-S. Lou, W.-T. Chen, W. Diyatmika, J.-H. Lu, C.-T. Chang, P.-W. Chen, J.-W. Lee, Curr.
Opin. Chem. Eng., 36 100782 (2022).
[2] S. K. Bachani, C.-J. Wang, B.-S.. Lou, L.-C. Chang, J..-W.. Lee, J. Alloys Compd., 873
159605 (2021)

PL-2

Plasma Agriculture Works with Plasma Treated Nitric Oxide Water(PTNOW) in Korea
Eun Ha Choi1, Ihn Han1, Youn June Hong1, Jinsung Choi1, Gyu Sung Cho1
1

Plasma Bioscience Research Center, Kwangwoon University, Seoul, Korea
ehchoi@kw.ac.kr

Plasma treated NO water (PTNOW) irrigation induced NO and H2O2 levels increase in theextracellular space. From the extracellular space NO and H2O2 levels either directly transport
into cell cytoplasm through aquaporin or induce the production of H2O2 from NADH oxidase,chloroplasts, peroxisome, and NO from mitochondria. NO and H2O2 both activate theproduction of other RONS, such as superoxide ion, peroxynitrite, and hydroxyl radicals in thecytoplasm, which causes lipid oxidation at higher concentrations. NO and H2O2 both induce theexpression of PR proteins, antioxidant enzyme activity, SA and JA pathway enzymes via
MAPK signaling pathways. All these defense proteins and phytohormones strengthen the plant
pathogen defense pathway [1].
Demonstration project for plasma agriculture with PTNOW in Korea will be introduced fortranslation to field site from laboratory. For this project the multicylinder dielectric barrier
plasma source has been developed for the major production of NO, from which some of other
ROS could be controlled and adjusted for the respective their applications under low power
consumption less than 150 W. The plasma characteristics of multicylinder dielectric barrier
plasma source as well as its electrical properties will also be described for mutual
understandings.
Especially the plasma agriculture demonstration is being performed at Yeon-Chon
Agricultural Technical Center (ATC), Kyunggi Province, and other region’s ATC for lettuce,
strawberry, radish, and basil. Also we will discuss the many other applications to odor removalfrom piggery or animal farms based on the nonthermal atmospheric pressure plasma.
[1] B. Ahikari, M. Adhikari, B. Ghimire, G. Park, E. H. Choi, Sci. Rep. 9,16080 (2019)

PSLO-KN-1

Hydrogen Isotope Behavior in Tungsten and RAFM Steels
Minyou Ye, Ze Chen
School of Nuclear Science and Technology, University of Science and Technology of China
Anhui, Hefei 230026, China
yemy@ustc.edu.cn

The transport and retention of hydrogen isotopes is of vital importance for the realizationof future commercial fusion reactors, because it is closely related to plasma operation, fuelrecycling and safety. However, the hydrogen isotope behavior in fusion reactor materials is notwell understood. Reduced activation ferritic-martensitic (RAFM) steel and tungsten (W) arepromising candidate structural materials and first wall materials, respectively. In thispresentation, we reported the deuterium permeation and retention behaviors of seven kind of
RAFM steels and two kind of W. Gas-driven permeation (GDP) method was used to investigate
the deuterium permeability, diffusivity, and solubility of the studied materials, with loadingpressure up to 1×105 Pa. For RAFM steels, the results indicates that the deuterium permeability
has little materials dependence. In contrast, the deuterium diffusivity of seven studied RAFMs
showed significant variation. And W show lower permeability and diffusivity than RAFMs in
the working temperature range. The influence of low-energy high-flux plasma irradiation on
deuterium permeation in W has also been studied. Besides, thermal desorption spectroscopy(TDS) was performed to assess the retention behaviors of RAFMs and W with a temperature
ramping rate of 0.5 K/s following a static thermal gas charging. Dominant desorption peak of~1000 K was observed for W while ~500 K for RAFMs. And the retention of deuterium in
RAFMs is about 1 to 2 order of magnitude higher than W. Finally, microstructural featurescontributing to the desorption and retention properties was discussed.

PSLO-KN-2

Beneficial Effects of Helium in Tungsten in Context of Fusion Plasma andWall Interactions
Guang-Hong Lu1,*, Yue Yuan1, Hong-Bo Zhou1, Yu-Hao Li1, Long Cheng1, Wei-Zhong
Han2, and Si-Mian Liu2
12

School of Physics, Beihang University,
Beijing 100191, China
LCheng@buaa.edu.cn

Center for Advancing Materials Performance from the Nanoscale, State Key Laboratory for MechanicalBehavior of Materials, Xi'an Jiaotong University,
Xi’an, 710049, China

Helium is a typical impurity in nuclear materials. Its closed-shell electronic structure leads
to a significant "electrophobic" property [1], which makes helium atoms easy to form clusters
or bubbles in metals. Helium in fusion reactor materials is mainly derived from the product of
deuterium-tritium fusion reaction and the transmutation during neutron irradiation, of which
the former is mainly a surface effect and the latter is a body effect. Helium is generally
considered to be hazardous that can lead to degradation of material properties. Interestingly, aseries of recent works have shown that helium, regardless of its source, exhibits "beneficial"effects, especially in tungsten as a plasma-facing material, in terms of the microstructural
evolution, hydrogen isotope retention and mechanical properties of materials. These studies
have deepened the understanding and knowledge of helium effects in metals.
Helium could effectively retard recrystallization and displacement damage in tungsten
due to the effect of helium on microstructure evolution, including the effect on grain boundary
migrations, self-interstitials migrations, and the recombination between self-interstitials andvacancies. These microstructural changes could potentially slow down the degradation oftungsten exposed to fusion edge plasma and neutrons. Hydrogen isotopes retention intungsten could be greatly reduced by helium. The formation of helium-rich layer could
enhance hydrogen trapping but reduce hydrogen diffusion towards the bulk, which therefore
reduce total hydrogen retention. In other metals, helium could enhance mechanicalproperties of metals. Helium nano bubbles serve as shearable obstacles of dislocations,
therefore slow down the dislocation motion, and active internal dislocation sources which
promote the uniform nucleation of dislocations in single cystalline copper.
This presentation will focus on the beneficial effects of helium in tungsten and emphasizethat the relevant research efforts could provide new ideas for solving problems related toplasma-wall interactions and tritium self-sustainability in fusion reactors.
[1] Hong-Bo Zhou, Guang-Hong Lu, et al., Acta Materialia 2016, 119: 1-8.

PSLO-KN-3

Effect of co-deposition on helium plasma irradiation to tungsten
Shin Kajita1,3, Hirohiko Tanaka2,3, and Noriyasu Ohno3,2
1

2

Graduate School of Frontier Sciences, The University of Tokyo
Kashiwa, Chiba 277-8561, Japan
kajita@k.u-tokyo.ac.jp

Institute of Materials and Systems for Sustainability, Nagoya University
Nagoya 464-8603, Japan
3

Graduate School of Engineering, Nagoya University
Nagoya 464-8603, Japan

In fusion devices, the divertor material (tungsten) is subjected to significant heat and particle
loads. The particles include helium atoms in addition to hydrogen isotopes due to the nuclear
reaction of deuterium and tritium. The interaction of helium with tungsten is special anddifferent from those of hydrogen and hydrogen isotopes. Helium nanobubbles and fiberform
nanostructures called fuzz can be formed on the surface [1]. In particular, because fuzz cansigificantly change the physical properties including thermal conductivity, field electron
emission property, sputtering yield, particle reflection, and so on, the growth feature has been
extensively investigated worldwide. One of the unknown effect on the fuzz growth is the effectof co-deposition. Since co-deposition occurs in fusion devices, it is important to investigate it
further.
The co-deposition effect was investigated in the divertor simulator NAGDIS-II. A
sputtering source (tungsten wire) was placed near the sample and the growth of fuzz on thesample was studied. It was found that fuzz growth is significantly accelerated, say by several
orders of magnitude, and mm thick fuzz isgrown on the surface under certain conditions[2]. It was also found that the growth ofnanotendril bundles (NTBs), which areseveral tens of m high bundled fiberform
structures, is also related to the deposition
effect [3].
Figure 1 shows a scanning electron
microscope (SEM) image of fuzz grown ontungsten mesh with tungsten deposition. The
growth rate on the mesh was different fromthat on the tungsten plate. By comparing the
growth rate on different sized meshes, it wasFig. 1: Fiberform nanostructure grownfound that the helium flux and the tungsten on tungsten mesh during tungsten deposition
deposition rate are two important factors for in helium plasma [4].
the initial growth.
[1] S Kajita, W Sakaguchi, N Ohno, N Yoshida, T Saeki, Nuclear Fusion 49 (2009), 095005.
[2] S Kajita, S Kawaguchi, N Ohno, N Yoshida, Scientific Reports 8 (2018), 56.
[3] D Hwangbo, S Kajita, N Ohno, P McCarthy, JW Bradley, H Tanaka, Nuclear Fusion 58(2018), 096022.
[4] K Hori, S Kajita, R Zhang, H Tanaka, N Ohno, Scientific Reports 13 (2023), 5450.

PSLO-I-1

Performance of tungsten materials under sequential high heat flux
loading and deuterium plasma exposure
Yue Yuan1, Peng Wang2, Henri Greuner2, Wei Liu3, Long Cheng1, Guang-Hong Lu1
1

2

School of Physics, Beihang University, Beijing 100191, China
Max-Planck-Institut für Plasmaphysik, EURATOM Association, 85748 Garching, Germany
3
Department of Material Science and Engineering, Tsinghua University, Beijing 100084,
China
Tungsten (W) and W based materials, the most promising candidates for plasma facing

materials for future fusion reactors, will be exposed to extreme conditions during operations,such as high heat flux (HHF) loads and intense particle irradiations (i.e. hydrogen isotope ionsand energetic neutrals). HHF loads can lead to recrystallization, and the more destructive
surface melting issue of W materials. Such recrystallized and resolidified W materials shouldstill withstand further deuterium (D) irradiation in subsequent operation. It is thus imperative
to assess the D retention in the recrystallized and resolidified W materials after additional D
exposure.
In this work, we first prepare recrystallized and resolidified W and W-1 wt% La2O3
samples by applying a HHF loading (≤ 23 MW/m2) above the melting threshold in the highheat flux test facility GLADIS (IPP-Garching). Thereafter, they are exposed to D plasma in a
low-pressure steady-state electron cyclotron resonance (ECR) plasma chamber ‘PlaQ’. The
thermal desorption spectroscopy (TDS) measurements indicate that D retention reduces by~40% after shallow surface melting for both of the two W grades. On the other hand, Dretention in the WL10 is almost double that in the pure W regardless of whether surface
melting occurs or not. The TDS spectra exhibit two main desorption peaks at around 550 K
and 700 K, which largely corresponds to grain boundaries and voids respectively. However,an additional peak appears unexpectedly around 1070 K for the melted WL10. We attribute
this additional high-temperature peak to the formation of the formation of the hydrogen
absorbing metal La in the resolidified layer, which is confirmed by transmission electron
microscopy and energy dispersive X-ray spectrometry results.

B-KN-1

Low-temperature plasma as a ferroptosis inducer in cancer cells
Shinya Toyokuni1,2, Hao Zheng1, Yasumasa Okazaki1, Kae Nakamura2, Hiroaki Kajiyama2,
Hiromasa Tanaka2, Keiji Ishikawa2 and Masaru Hori2
1

Department of Pathology and Biological Responses, Nagoya University Graduate School of Medicine
65 Tsurumai-cho, Showa-ku, Nagoya, Japan
2
Center for Low-temperature Plasma Sciences
Furo-cho, Chikusa, Nagoya 464-8603, Japan

Iron is an essential nutrient for every species on the earth. However, iron provides double
edged sword; its deficiency causes anemia in mammals but its excess leads to toxic effects.
Indeed, excess iron has been associated with carcinogenesis [1]. Ferroptosis is defined as a formof regulated necrosis, characterized by lipid peroxidation through high iron (oxidants)/sulfur(antioxidants) ratio [2]. Considering that cancer cells generally reserve more catalytic Fe(II)than non-tumorous counterparts, many iron-induced carcinogenesis models, including
asbestos-induced mesothelioma, suggest that cancer is a state of “iron addiction withferroptosis-resistance.” [3] The concept of ferroptosis is now expanding, and ferroptosis isobserved not only in pathological conditions (cancer cells after chemotherapy; neurons withaging, etc.) but also in certain physiological conditions.
Low-temperature plasma (LTP) is a novel physical technique that emits abundant electrons,
resulting in a variety of ROS products by reaction with ambient air. Exposure of LTP tobiomolecules, cells or tissues causes oxidative stress in situ, leading to DNA breaks and lipid
peroxidation products, such as HNE. We found that NTP exposure is highly dependent on Fe(II)in situ, causing cancer cell-specific ferroptosis, which was associated with autophagy activationand lysosome genesis. We are trying to visualize ferroptosis in formalin-fixed paraffinembedded pathology specimens with new monoclonal antibodies, which revealed physiologicalferroptosis [4].
NTP-activated Ringer’s lactate (PAL) is another modality at the preclinical stage as
cancer therapeutics, based on more stable reactive species. PAL specifically kills
malignant mesothelioma (MM) cells, employing lysosomal
nitric oxide as a switch from autophagy to ferroptosis [5].
Here we studied cytosolic iron regulations in MM and othercancer cells in response to PAL exposure. PAL can sensitize
MM cells to ferroptosis by remodeling not only nitric oxide
but also cytoplasmic iron homeostasis, where glutathione andpoly(rC)binding protein 1/2 (PCBP1/2) play critical roles.
PCBPs can be novel targets for cancer therapeutics.
(Funding: JSPS Kakenhi JP19H05462)
[1]
[2]
[3]
[4]
[5]

Fig. 1 Low-temperature plasma as a ferroptosis inducer in cancer cells
Toyokuni S, et al. Ferroptosis at the crossroads of infection, aging and cancer. Cancer Sci
2020;111(8):2665-2671.
Stockwell BR, et al. Ferroptosis: A Regulated Cell Death Nexus Linking Metabolism, Redox
Biology, and Disease. Cell 2017;171(2):273-285.
Toyokuni S, et al. Iron and thiol redox signaling in cancer: An exquisite balance to escape ferroptosis.
Free Radic Biol Med 2017;108:610-626.
Zheng H, et al. Embryonal erythropoiesis and aging exploit ferroptosis. Redox Biol 2021;48:102175.
Jiang L, et al. Lysosomal nitric oxide determines transition from autophagy to ferroptosis after
exposure to plasma-activated Ringer's lactate. Redox Biol 2021;43:101989.

B-I-1

Assessment of Probability Estimation on Human Tissue-Derived
Fibroblast/Stromal Cells Response to Non-Thermal Biocompatible Plasma
Ihn Han1, 2 and Eun Ha Choi1, 2
1 Department of Plasma-Bio Display, Kwangwoon University, Kwangwoon University, Seoul 01897, Republic of Korea
2 Plasma Bioscience Research Cente, Kwangwoon University, Kwangwoon University, Seoul 01897, Republic of Korea
I.Han hanihn@kw.ac.kr

Non-thermal nano-biocompatible plasma (NBP) has emerged as a powerful biomedical toolwith the potential to revolutionize tissue regeneration strategies. This study delves into theeffects of NBP on human tissue-derived fibroblasts and mesenchymal stem cells (hMSCs),
examining their responses in terms of cellular mobility, collagen synthesis, and osteogenic
differentiation.
NBP treatment has been demonstrated to significantly enhance fibroblast mobility,
facilitating their directed migration towards wound sites. This phenomenon holds the potential
to expedite wound healing by ensuring the effective recruitment of essential cells to the site of
injury. Moreover, NBP treatment stimulates the production of collagen, a critical extracellularmatrix component essential for tissue remodeling. Collagen generation not only reinforces
tissue structure but also supports the regenerative processes vital for complete healing.
Furthermore, this study uncovers NBP's impact on hMSCs, revealing its potential topromote osteogenic differentiation. NBP-treated hMSCs exhibit an increased propensity todifferentiate into osteoblasts, the cells responsible for bone formation. Additionally, thesedifferentiated osteoblasts show heightened mineralization capacity, indicating their potential inaccelerating bone tissue regeneration.
This research contributes to our expanding knowledge of NBP's potential in tissue
engineering and regenerative medicine. By enhancing fibroblast mobility and collagengeneration while also promoting osteogenic potential, NBP presents an integrated approach to
expedite wound healing and tissue remodeling. The quantified estimate of enhanced cellularresponses obtained through statistical analysis offers a solid foundation for harnessing NBP's
potential in innovative biomedical applications.
In conclusion, this study bridges the gap between non-thermal nano-biocompatible plasma
and tissue regeneration by elucidating its multifaceted effects on fibroblasts and hMSCs. By
addressing cellular mobility, collagen synthesis, and osteogenic differentiation, NBP holds
promise as a transformative approach for advancing tissue healing and regenerative therapies.

B-I-2

Cold atmospheric plasma facilitates wound healing for type 2 diabetes andskin flap treatments
BS Lou1,2, SH Chen3, CW Hou1, TP Chu4, and JW Lee4,5,6
1
Chemistry Division, Center for General Education, Chang Gung University, Taoyuan, Taiwan
Department of Orthopaedic Surgery, New Taipei Municipal TuCheng Hospital Chang Gung Memorial
Hospital, Taoyuan, Taiwan. blou@cgu.edu.tw
3
Department of Plastic and Reconstructive Surgery, Chang Gung Memorial Hospital, Chang Gung University
and Medical College, Taoyuan, Taiwan
4Department of Materials Engineering, Ming Chi University of Technology, New Taipei City, Taiwan
5Center for Plasma and Thin Film Technologies, Ming Chi University of Technology, New Taipei City, Taiwan
6Department of Mechanical Engineering, Chang Gung University, Taoyuan, Taiwan
2

Cold atmospheric plasma jet (CAPJ) has been employed in various biomedical applications
based on their functions in bactericidal activity and wound healing. The effect of CAPJ
generated by a particular composition of gases on wound closure and the underlying
mechanisms that regulate wound healing signals had been investigated. He/Ar-CAPJ
effectively induced keratinocyte proliferation and migration mediated through the activation ofepithelial-to-mesenchymal transition (EMT) and cell cycle progression, which was evidenced
by a decrease in E-cadherin levels and increases in N-cadherin, cyclin D1, Ki-67, Cdk2, and pERK levels. Rat wound healing studies showed that He/Ar-CAPJ treatment facilitatedgranulation tissue formation and mitigated inflammation in cutaneous tissue, resulting inaccelerated wound closure. Furthermore, animal models were developed to evaluate the CAPJ
treatment effect for diabetic rats in different stages as it progresses and angiogenesis for skinflap.
[1] BS Lou, JH Hsieh, CM Chen, CW Hou, HY Wu, PY Chou, CH Lai, JW Lee Bioengineeringand Biotechnology 8, 683. 1-11 (2020).
[2] BS Lou, CH Lai, TP Chu, JH Hsieh, CM Chen, YM Su, CW Hou, PY Chou, JW Lee. Journalof Clinical Medicine, 1930 (2019).

B-I-3In vivo toxicity test of DBD plasma activated water by using Zebrafish
Ying-Hung Chen1, Yi-Jun Chung2, Chen-Shin Chen2, Yen-Lun Chung2, Yu-Ren Wei2, PingYen Hsieh1 and Ju-Liang He1,2
Institute of Plasma, Feng Chia University
No. 100, Wenhwa Road, Seatwen District, Taichung City 407102, Taiwan.
1

jlhe@o365.fcu.edu.tw

Department of Materials Science and Engineering, Feng Chia University
No. 100, Wenhwa Road, Seatwen District, Taichung City 407102, Taiwan.

2

Climate change increases the need for efficient and sustainable technologies in food andagriculture. Plasma-activated water (PAW) is a new and emerging technology with potential
applications in food and agriculture. PAW is water that has been treated with cold atmosphericplasma (CAP). The presence of reactive oxygen and nitrogen species (RONS) can produce avariety of synergistic effects on animals, plants, and food. PAW has been verified to effectively
improve plant growth, crop preservation, food sterilization, and animal cell activation. However,humans will eventually eat these processed animals, plants, or food, and PAW's biotoxicity
must be considered. The biotoxicity of PAW is an important indicator for evaluating its safety.
The zebrafish embryo acute toxicity test is a commonly used evaluation method, which canassess the impact of PAW on fish in the early stages of development.
Here we present the results of the in vivo toxicity study on dielectric barrier discharge(DBD) plasma activated water by using Zebrafish as the test sample. The motive of such a study
is to understand how the concentration of main active species NO3-and RONS in PAW canaffect Zebrafish survival, so as to laterally figure out how the toxicity brought by NO3- can be
tolerated by animal body. Experimentally, a set of NO3- water solution make-up with different
concentrations was deployed for comparison, and a set of PAW with different NO3concentrations was prepared at different plasma treatment time. Both sets were underwent
Zebrafish test. The results of the tests will be reported. The research results will provide ascientific basis for the safety evaluation of PAW and provide guidance for the application of
PAW in food and agriculture.

B-O-1

Chemically Active Compounds Formed in Low-temperature Plasma
Treated Liquids for Cancer Treatment
Camelia Miron1, Hiromasa Tanaka1, Taishi Yamakawa1, Du Lyin1, Hiroki Kondo1, Hiroshi
Hashizume1, Takashi Kondo1, Kenji Ishikawa1, Shinya Toyokuni1,2, Masaaki Mizuno3, andMasaru Hori1
1

Center for Low-temperature Plasma Sciences, Nagoya University,
Furo-cho, Chikusa-ku, Nagoya 464-8603, Japancamelia@plasma.engg.nagoya-u.ac.jp

2
Department of Pathology and Biological Responses, Nagoya University,
Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
3

Center for Advanced Medicine and Clinical Research, Nagoya University Hospital,
65 Tsurumai-cho, Showa-ku, Nagoya 466-8560, Japan

With the promising perspective of becoming a new type of oncological therapy, lowtemperature plasma (LTP) has recently gained much attention [1,2]. The liquids treated with
LTP contain a variety of reactive species, including molecular, atomic, radical, and ioniccompounds. These interactions are changing the chemical properties of the irradiated liquids,
reported to have anti-cancer activity [3]. Chemically active species identified in various plasmatreated liquids, such as Ringer`s lactate or chitosan depend on the irradiation time and on thefeeding gas mixture (argon, nitrogen, and oxygen) used in the discharge. The degree ofpolymerization is also modified by plasma treatment, depending on the chemical compositionof the initial compounds used in the experiments.
The cleavage of radicals from the liquid precursors, such as methyl radicals, is followed by theformation of key intermediate products (peracetic acid, 2-2-dihydroxyacetic acid,carboxymethyl radicals, or oligosaccharides). Further interactions in plasma result in theformation of more complex compounds, such as glyceric acid, acetic anhydride, ethyl acetate,or tricarballylic acid with stimulatory or inhibitory effects on cell viability. The killing
selectivity towards cancer cells is influenced by the gas mixture used in the discharge, but also
by the chemical composition of liquids, higher molecular weight compounds used in our studies
being very effective in destroying the cancer cells. Plasma generates a mixture of certain
chemically active species in the exact amount able to induce cytotoxic effects on breast cancer
cell lines (MCF-7), leaving the non-tumorigenic epithelial cell lines (MCF-10A) unharmed.
The adjustment of the plasma parameters gives the possibility of engineering liquids that induce
a selective generation of chemical compounds responsible for the antitumor activity.
[1] S. Toyokuni, Y. Ikehara, F. Kikkawa, and M. Hori, Plasma medical science (AP, Elsevier,2018).
[2] Y. Liu, K. Ishikawa, C. Miron, H. Hashizume, H. Tanaka, and M. Hori, Plasma Sources Sci.
Technol., 30, 04LT03 (2021).
[3] C. Miron, K. Ishikawa, S. Kashiwagura, Y. Suda, H. Tanaka, K. Nakamura, H. Kajiyama, S.
Toyokuni, M. Mizuno, M. Hori, Free Radical Research, 57,104 (2023).

S-I-1

Recent trends of plasma deposition technologies
for the development of next-generation electronic devices
Jaeho Kim
Samsung Electronics Co., Ltd
1-1 Samsungjeonja-ro, Hwaseong-si, Gyeonggi-do 18448, Korea
jplasma.kim@samsung.com

Recently, the development of advanced electronic materials are required to realize nextgeneration electronic devices. In special, 2D materials such as graphene, MoS2 and h-BN havebeen lised as strong candicates in the roadmap for future electronic devices [1]. Plasma-based
technlogy is the most promising method for the lab-to-fab transition of 2D materials insemiconductor industry.
In this talk, we will review recent trends of plasma deposition technology including PECVD(plasma enhaced chemcial vapor depsotion) and PEALD (plasma enhanced atomic layer
deposition) for the depostion of 2D materials. The growth mechanismis of 2D materials inplasma and the limitation of conventional plasma technology are discussed. The strategies todevelop an advanced plasma deposition equipment which allows the lab-to-fab transition of 2D
materials will be also discussed.
[1] International Roadmap for Devices and Systems (IRDS™) 2022 Edition.

S-KN-1

On the mechanism of Arcing phenomenon in low temperature plasma
Shinjae You1,2, Sijun Kim1,2, Chulhee Cho1, Daewoong Kim3, and Sanghoo Park4
1

2

3

4

Department of Physics, Chungnam National University
Daejeon 34134, Republic of Korea
sjyou@cnu.ac.kr

Institute of Quantum Systems (IQS), Chungnam National University
Daejeon 34134, Republic of Korea

Department of Plasma Engineering, Korea Institute of Machinery and Materials (KIMM),
Daejeon 34103, Republic of Korea

Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science andTechnology (KAIST), Daejeon 34141, Republic of Korea

For more than 120 years, arcing, a transient high-density discharge, has attracted significant
attention in both industrial and academic fields. Arcing leads to substantial damage on material
surfaces, regardless of material properties. However, its underlying physics, particularly inmoderate-density plasmas (ranging from 1009 to 1011 cm-3), remains not entirely understood.
This study explored the mechanism triggering arcing on an arcing-inducing probe (AIP)
within a radio frequency capacitively coupled plasma environment (RF-CCP). Detailed
information about the experimental setup can be found elsewhere [1]. We examined arcing bymeasuring its voltage (VAIP) and current waveforms, capturing spatiotemporal images, andanalyzing optical emission spectra. We found that electron emission from the arcing spot
dominates both the arcing current and the emitted light, despite the existence of energetic ionsand electrons produced by the capacitively coupled plasma. Additionally, we observed peaksin the emission lines caused by evaporated metals in the optical emission spectra, suggesting asufficiently high temperature at the arcing spot to induce surface vaporization.
Based on these results, we propose that the initiation of arcing in a moderate-density plasma
results from thermo-field emission and metal evaporation at the arcing spot, driven by intense
Ohmic heating. This interplay triggers ionization collisions between emitted electrons andvaporized atoms, initiating an electron cascade near the emission point and eventually leading
to the generation of arcing. While our proposed mechanism aligns with conventional
understanding in vacuum arc scenarios, its significance lies in its examination under the RFCCP environment with direct measurement of arcing voltage and current, as well as its
spatiotemporal image analysis. Furthermore, our experimental results imply the presence of
yet-unveiled mechanisms, such as the initiationof field emission, transition to thermo-fieldemission, and the influences of arcing on RFCCP.
[1] S. -J. Kim, Y. S. Lee, C. -H. Cho, M. -S.
Choi, I. -H. Seong, J. -J. Lee, D. -W. Kim, andS. -J. You, Scientific Reports, 12, 20976 (2022).
Fig. 1: Spatiotemporal image of arcing at
VAIP of -75 V, pressure of 171 mTorr, and RF
power of 40 W.

S-KN-2

Enterprise Intelligentization of Semiconductor Manufacturing in Taiwan
Shu-Kai S. Fan
Department of Industrial Engineering and Management, National Taipei University of Technology
No. 1, Sec. 3, Zhongxiao E. Rd., Taipei 106344, Taiwan
morrisfan@ntut.edu.tw

This talk will discuss state-of-the-art technologies related to data science and their applicationsin the current semiconductor practice, particularly focused on the front-end-of-line processes.
It addresses a new transformation framework, by making the transition from processtransformation to artificial intelligence (AI) transformation. The major purpose is to harness thevolatility, uncertainty, complexity and ambiguity (VUCA) situations in an attempt to encourageradical innovation in front-end-of-line (FEOL) semiconductor manufacturing. It will explore
the advantages of these technologies and how they can create insights and values forsemiconductor fabrication during the era of AI Economy.

S-KN-3

Ammonia-free Plasma-enhanced MOCVD for Nitride Semiconductors
Hisashi Yamada1,2, Naoto Kumagai1,2, Tetsuji Shimizu1,2, Xue-lun Wang1,2, Jaeho Kim1,2*,
and Hajime Sakakita1,2
1

AIST-NU GaN Advanced Device Open Innovation Laboratory (GaN-OIL),
National Institute of Advanced Industrial Science and Technology (AIST),
Furo-cho, Chikusa, Nagoya, Aichi 464-8601, Japanhisashi-yamada@aist.go.jp
Research Institute for Advanced Electronics and Photonics (RIAEP),
National Institute of Advanced Industrial Science and Technology (AIST),
Tsukuba Central 2, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan
2

Nitride semiconductors, such as gallium nitride (GaN), aluminum nitride (AlN), indium
nitride (InN), and these alloy compounds, can contribute the SDGs society that meets anenvironmentally firiendly manufacturing process without using toxic precursors, such as AsH3
and PH3 for InGaAs/InP system. InN has the bandgap of ~0.7eV, the smallest effective mass
(0.07 m0), the highest electron mobility (>4000 cm2/Vs), and the highest saturation drift
velocity (>5 × 107 cm/s) among nitride semiconductors. These features are promising not only
for next-generation (6G) high-frequency devices but also for near-infrared opt-electronic
devices. Furthermore, by layer stacking with InGaN and GaN, it is expected to realize full-color
light-emitting diodes (LEDs) and tandem-type solar cells. However, the conventional metalorganic chemical vapor deposition (MOCVD) consumes large amounts of NH3 (ex. for the GaN
case, 1000-10,000 times more than the Group III elements) due to its low decomposition
efficiency and elimination of residual impurities. The situation is more severe for InGaN and
InN owing to the weaker In-N bonds, which requires lower growth temperatures. This resultsin almost no growth windows for high-In-content (In>0.4) InGaN and InN.
In order to overcome these issues, we have developed a microstrip-line microwave nitrogenplasma source[1] and integrated with MOCVD[2]. The plasma source provides an active nitrogenradical density of ~2 × 1014 cm–3. This leads to the NH3 consumption down to 1/100 or lessusing NH3 plasma, and ultimately NH3-free manufacturing process using N2 plasma.
Furthermore, the plasma-enhanced MOCVD can expand the growth window toward the lower
growth temprature range.
InN crystal growth was demonstrated on a 2-inch GaN/Al2O3 (0001) template using
trimethyl indium (TMI) and N2 as the precursors. The growth temperature and pressure were
650℃ and 2kPa, respectively. The plasma power and nitrogen gas flow rates were 90W and 2
L/min, respectively. The ω/2Ө of the X-ray diffraction pattern confirms a (0002) peak. The
full-widths-at-half-maximum (FWHMs) of the X-ray rocking curve (XRC) for (0002) / (10-12)
are 618 / 999 arcsec, respectively. The total threading dislocation density is calculated as 2.4 ×
109 cm–2, which agrees with the cross-sectional TEM result. The photoluminesence at room
temperature reveals the peak energy and the FWHM of 0.687eV and 0.1 eV, respectively. The
plasma-enhanced MOCVD makes it possible to obtain high crystalline InN without using NH3.
[1] J. Kim, H. Sakakita, H. Ohsaki, and M. Katsurai, Jpn. J. Appl. Phys. 54, 01AA02 (2015).
[2] H. Sakakita, N. Kumagai, T. Shimizu, J. Kim, H. Yamada, and X.-L. Wang, Appl. Mater.
Today 27, 101489 (2022).
*Present affiliation: Samsung Electronics Co., Ltd.

WFPP-I-1

Property control of Ge and Si nanostructured films by high-pressure He
sputtering process for next-generation Li ion battery
Giichiro Uchida
Faculty of Science and Technology, Meijo University
1-501 Shiogamaguchi, Nagoya 468-8502, Japanuchidagi@meijo-u.ac.jp

Electric vehicles powered by Li-ion batteries are increasingly replacing gasoline-powered
vehicles toward the realization of a carbon-neutral society, and the development of highperformance Li-ion batteries that have high capacity for long-distance driving, high power for
rapid charging, and low degradation for long-term use is encouraged worldwide. Group-IV Si
and Ge are promising anode materials for Li-ion batteries because they have very hightheoretical capacities of 4200 and 1600 mAh/g, respectively, which are 4–11 times higher thanthe 372 mAh/g capacity of commercial carbon. However, the high-capacity Si and Ge materials
suffer large volume expansion during Li alloying reactions, and repeated cycling leads tomaterial pulverization from the current collector, resulting in performance degradation. In thepresent study, we propose an alternative plasma bottom-up process to fabricate Ge and Si
nanostructured films for Li-ion-battery anodes using plasma sputtering PVD. The important
advantage of our plasma sputtering PVD is that it employs a simple single-step procedure thatenables the direct fabrication of anode, where our method enables control of material properties
such as crystallinity, conductivity, and morphology.
The Ge and Si anode films were fabricated on a Cu disk using 13.56 MHz radiofrequency
magnetron sputtering.1,2) The Cu disk had a diameter and thickness of 15 mm and 80 m,
respectively, and was placed at the center of the substrate holder. The sputtering target of 1 inch
diameter was used. Ar or He gas was supplied from the direction of the target to the substrateholder, and the gas pressure was set to a high value of 100 to 500 mTorr. The distance between
the target and the substrate holder was 10 or 20 mm. The substrate holder was not heated orcooled during film deposition. As shown in fig. 1, the film morphology could be controlledfrom a 3D nanoporous to a 1D nanowire 60 nm(average)
202 nm(average)
morphology by changing plasma
condition. In particular, 1D nanowire
films were obtained under the special
sputtering conditions of a SiSn (3–6 at%)target and He discharge gas at a high
1 m
1 m
pressure of 100–500 mTorr. The 1D
nanowires consisted of an amorphous Si
core with high Li-ion capacity and acrystalline Sn shell with high electricalconductivity, which were suitablestructures for Li-ion-battery anodes.2)
We will discuss in detail the properties of
5 m
10 m
nanomaterials and the performance ofFig. 1: Various morphology of Si nanostructured films
lithium-ion batteries.
fabricated in the low-temperature plasma process.

[1] G. Uchida et al., Sci. Rep 12, 1742 (2022).
[2] G. Uchida et al., Sci. Rep. 13, 14280 (2023).

WFPP-I-2

A process for synthesizing melted tin-carbon core-shell
nanoparticles using dusty plasma
Munaswamy Murugesh and Koichi Sasaki
Division of Applied Quantum Science and Engineering,
Graduate School of Engineering, Hokkaido University, Sapporo 060-8628, Japanmurugesh@elms.hokudai.ac.jp

Energy management is a common interest in recent years with increasing awareness oversustainable development goals and increased utilization of energy resources. Particularly, phasechanging materials (PCM) for thermal storage have gained wide attention from recent decades.
The latent heat storage method is considered as one of efficient methods of thermal energy
storage; it relies on the storage material absorbing or releasing heat when it undergoes the phasechange between solid and liquid. This work is addressing the process development forsynthesizing tin-carbon core-shell nanoparticles that can be used as PCM.
To realize the robustness of the shell against the volume expansion of the core at the melting,
we constructed a process to deposit shell films around melted tin cores. As shown in figure 1(a),dc magnetron sputtering at a high pressure was used for synthesizing tin nanoparticles. The
gravity transported nanoparticles to the bottom of the chamber, where a capacitively coupled rf
plasma was generated using a ring electrode. Tin nanoparticles were trapped on the sheathboundary, and they were heated by the rf plasma. After the heating, we introduced methane todeposit amorphous carbon films around melted tin nanoparticles. Finally, core-shell
nanoparticles thus synthesized were collected by applying a positive bias voltage to a circularelectrode placed inside the ring rf electrode. Figure 1(b) shows TEM images of collected
nanoparticles. The spherical shapes of cores suggest that they were melted when trapped in therf plasma. We examined the melting characteristics of core-shell nanoparticles using TEM withthe sample heating ability. We observed the melting (the transition from crystalline toamorphous structures) of cores at the melting temperature of metallic tin, indicating negligible
oxidation of tin cores. In addition, we did not observe the break of shell films at the melting ofcores. The present work has demonstrated the usefulness of dusty plasma to deposit shell films
around melted cores.

Figure 1. a) Schematic of synthesis apparatus and b) TEM images of synthesized coreshell nanoparticles.

WFPP-I-3

Controlling the synthesis, transport, and surface coverage ofcarbon nanoparticles using plasma CVD
Shinjiro Ono1, Manato Eri1, Takamasa Okumura1, Kunihiro Kamataki1, Naoto Yamashita1,
Haruto Kiyama1, Naho Itagaki1, Kazunori Koga1, and Masaharu Shiratani1
1

Kyushu University, Motooka 744, Nishi-ku, Fukuoka 819-0395, Japans.ono@plasma.ed.kyushu-u.ac.jp

Controlling the deposition properties of nanoparticles is a fundamental and important topic
in plasma nanotechnology. In particular, carbon nanoparticles (CNPs) are widely applied in
optical and chemical applications such as photocatalysis and electrode materials [1, 2]. There
are many methods for synthesis of CNPs, including liquid-phase and spraying methods. Plasma
processes are useful methods through a simple process with little contamination [3]. So far, wehave revealed growth mechanism of Si nanoparticles in SiH4 plasmas and realized tosynthesized Si nanoparticles of 2 nm in size with a narrow size dispersion [4]. In this study, we
studied the synthesis, transport and deposition of CNPs using CH4 capacitively coupled plasma
CVD, which allows large-area deposition and is highly compatible with semiconductor frontend processes.
The experiments were performed using a plasma CVD reactor [5]. A powered electrodewas installed at 115 mm above a grounded substrate electrode. Mixture gas of Ar and CH4 wasintroduced from the top of the chamber. The flow rate of Ar and CH4 were 19 sccm and 2.6
sccm, respectively. Total pressure was set at 300 mTorr. A discharge frequency and voltage
were 28 MHz and 280 Vpp, respectively. To prevent unexpected agglomeration during CNPs
fabrication using plasma CVD, we performed a pulse-like discharge method with a cycle of 1
min ON and 1 min OFF. The CNPs were observed using transmission electron microscopy(TEM).
We have measured the size of CNP deposited on the substrate from the TEM image andobtained size distribution. The results show that the distribution of the formed CNPs is divided
into two groups. One group was small, with an average size of about 5 nm, while the othergroup was relatively large, with an average size of about 20 nm. From the size distribution, we
calculated the coverage Cp of CNPs by following equation.
𝐶𝑝 = 𝜋𝑟𝑝2 𝑛𝑝
where rp is radius of CNPs and np is area number density of CNPs. The Cp shows the ratio of
projected area of CNPs and total area. The Cp was linearly increased with the cycle number Ndof discharge. The CNP deposition takes place from Nd=10. The delay time of the CNPs
deposition might suggest the time to increase the temperature of the discharge electrode to
generate thermophretic force exerted on the CNPs[6].
[1] K. Koga et al., J. Phys, Conf. Ser., 518, 012020 (2014).
[2] L. Cao et al., J. Am. Chem. Soc., 133(13), 4754-4757 (2011).
[3] S. Nunomura et al., J. Appl. Phys., 99, 083302 (2006).
[4] T. Kakeya et al., Thin Solid Films, 506, 288 (2006).
[5] S. H. Hwang et al., Thin Solid Films, 729, 138701 (2021).
[6] S.H. Hwang et al., Diam. Relat. Mater., 109, 108050 (2020).

WFPP-KN-1

Plasmonic Plasma Process using Nanoparticles on Substrate
Takeshi Kitajima and Toshiki Nakano
National Defense Academy of Japan
1-10-20 Hashirimizu, Yokosuka, Kanagawa 239-8686, Japankitajima@nda.ac.jp

With the sophistication of various surface processes by non-equilibrium plasma in the gas
phase, it is a certain necessity in the direction of scientific and technological development toincorporate extended reaction fields due to the non-equilibrium nature of solid plasma and todesign integrated non-equilibrium reaction fields.
In this talk, we introduce the plasmon resonance of nanoparticles on silicon wafers andchemical reactions on the surface layer enabled by radicals supplied by plasma. Plasma
deposition can be performed at room temperature using plasmon resonance of nanoparticles on
Si substrates. The case using gold nanoparticles and the case using HfN nanoparticles are shown.
Gold is a typical plasmonic nanoparticle [1], and it is known that the energy accumulated
by surface plasmon resonance induced by light in the green region can induce various chemical
reactions through hot electron emission [2].
In the study, gold is irradiated onto the silicon substrate from the deposition cell in a vacuum,
and gold nanoparticles with an average diameter of 5 nm are grown by a self-assembly. Low
pressure inductively coupled nitrogen plasma delivers nitrogen radical species onto thesubstrate through a stainless-steel mesh. Light for plasmon excitation is supplied either fromthe plasma itself or from a light emitting diode. In this configuration, adsorbed radical species
are irradiated by hot electrons produced by plasmon de-excitation at the substrate surface,causing conversion of chemical bonds in the substrate. In the nitridation process of silicon
substrates, uniform and ultra-thin low defect SiON films were formed at room temperatureusing green excitation light at 530 nm. In the oxidation process, similar low defect SiO2 films
were formed at room temperature using oxygen plasma and 850-nm near-infrared light.
HfN nanoparticles are known as an alternativeplasmonic material to gold. By nitridating Hf
nanoparticles generated by the self-assembly method
and forming HfN nanoparticles, it is possible todeposit films on silicon substrates in the same way, inwhich case HfSiON films can be formed. Hot
electrons from plasmon deexcitation allow
dissociation of the SiO2 passive layer at room
temperature, resulting in interlayer transport of Si toenable film deposition.
This talk will also introduce the future vision of
surface processes enabled by plasmonic plasma
processes.
[1] V. Amendola, R. Pilot, M. Frasconi, O.M.
Maragò, and M.A. Iatì: J. Phys.: Condens. Matter
29, 203002 (2017).
[2] C. Clavero: Nature Photonics 8, 95 (2014).

Fig.

1:

Basic

designofplasmonic plasma process with
nanoparticles.

PL-3

Exploration of Atmospheric Pressure Plasma Technique in the Surface
Modification on Anode Material for High–rate Lithium–ion Battery and Rapid
Organic Fertilizer Manufacturing for Sustainable Farming
Yuan-Tai Lai1, Che-Ya Wu1, Shih-Nan Hsiao2, Masaru Hori2, Shao-Hsuan Chin1, Pin-Hao Huang1,
Yun-Chen Chan1, Jenq-Gong Duh1*
1. Department of Materials Science and Engineering, National Tsing-Hua University, Hsinchu, Taiwan
2. Center for Low-temperature Plasma Sciences (cLPS), Nagoya University, Nagoya, Japan*Corresponding Author e-mail: jgd@mx.nthu.edu.tw
Atmospheric pressure plasma (APP) is an emerging technology, which has attracted the attentionof scientists globally due to its combination of low cost, simplicity, and wide applications. It is shownthat APP could be successfully used in materials science and manufacturing for the deposition of
coatings, surface modifications, and treatments. In this study the recent developments in theapplications of APP on energy materials and novel agriculture field would be presented.
Lithium ion batteries (LIBs), as the key technology in electrical energy storage systems, areapplied in wide possibilities for next-generation electronics because of their high energy density, long
lifespan, high operating voltage. Nowadays, with the rapid development of electric vehicle, thedemands for battery have been focused on high power density and long cycle life. The APP has beenused for LIBs anode materials treatment to meet requirements. The surface modification could result in
the enhancement of electrochemical performance with stable capacity retention and high columbic
efficiency and APP irradiation introduced into the manufacturing process of lithium ion batteries is a
facile, green and scalable post-fabrication treatment approach.
Recent studies reveal that APP improves the electrochemical performance by N-doped decorationon conductive carbon, electrolyte wettability enhancement on PVDF binder, and defects manufacturing
in TiNb2O7 anode materials. Good wettability of surface free energy to 51.0 mJ/m2 in the APP-treatedsample contributes to improved cycling performance. Both N-doped carbon and the modified TNO
promote the high-rate capability. The C-rate performance of APP treated improves by over 250 % at 10
C as compared to the non-treated one. This work demonstrates a potential solution to achieve aroll-to-roll modification without any complex synthesis processes, which is a promising technology forthe affordable manufacturing of lithium-ion battery anode.
In addition, APP applications could be extended into the agriculture field as a powerful tool for
non-thermal processing. For the enhancement of germination and seedling stages, direct and indirect
plasma treatment can interact with seeds and change their surface characteristics by etching,introducing functional groups or giving the essential nutrients. Recently, enhanced utilization oforganic waste for fertilizer has significant impact for worldwide economy and ecology. The explorationof APP has also been expanded into food recycling areas. Using the plasma can help to promote theutilization and efficiency. Recent study has revealed that the plasma activated water (PAW) could
rapidly react with organic waste to produce extra nitrate fertilizer (NO3-). Herein, it is reported for the
first time on organic wastes treated with PAW, implying an innovation way to rapid organic fertilizer
manufacturing processes for sustainable farming in the novel agriculture related field.

PL-4

Plasma-Enhanced Atomic Layer Etching for Metals and Dielectric Materials

Heeyeop Chae
School of Chemical Engineering, Sungkyunkwan University (SKKU),
Suwon, 16419, Republic of Korea

The critical dimensions of semiconductor devices are continuously shrinking with 3D device
structure and are approaching to nanometer scale. The demand for dimension control in angstromlevel is drastically increasing also in etching processes. Atomic layer etching (ALE) processes arebeing actively studied and developed for various semiconductor and dielectric materials as well as
metals. In this talk, various plasma-enhanced ALE (PEALE) processes will be discussed for isotropic
and anisotropic patterning of metals and dielectric materials such as molibdenum, ruthenium,
cobalt, titanium nitride, tantalum nitride, halfnium oxide, zirconium oxides. [1-9] Typical ALE
processes consist of surface modification step and removal step. For the surface modification,
various fluorination, chlorination and oxidation schemes were applied including fluorocarbon
deposition, halogenation, oxidation with radicals generated plasmas. For the removal or etching
step, various schemes were applied including ion-bomardment, heating, ligand volatilization,
ligand exchange, and halogenation. The surface characteristics and requirements of plasmaenhanced ALE will be also discussed.
1) K. Koh, Y. Kim, C.-K. Kim, H. Chae, J. Vac. Sci. Technol. A, 36(1), 10B106 (2017)2) Y. Cho, Y. Kim, S. Kim, H. Chae, J. Vac. Sci. Technol. A, 38(2), 022604 (2020)3) Y. Kim, S. Lee, Y. Cho, S. Kim, H. Chae, J. Vac. Sci. Technol. A, 38(2), 022606 (2020)
4) D. Shim, J. Kim, Y. Kim, H. Chae, J. Vac. Sci. Technol. B., 40(2) 022208 (2022)
5) Y. Lee, Y. Kim, J. Son, H. Chae, J. Vac. Sci. Technol. A., 40(2) 022602 (2022)
6) J. Kim, D. Shim, Y. Kim, H. Chae, J. Vac. Sci. Technol. A., 40(3) 032603 (2022)
7) Y. Kim, H. Chae, Appl. Surf. Sci., 619, 156751 (2023)
8) Y. Kim, H. Chae, Appl. Surf. Sci., 627, 157309 (2023)
9) Y. Kim, H. Chae, ACS. Sustain. Chem. Eng., 11, 6136 (2023)

PSLO-KN-4

Overview of plasma heat exhaust studies in the DIFFER linear devices
I.G.J. Classen1, T.W. Morgan1, H.J. van der Meiden1, G.G. van Eden1, J. van den Berg1, K.
Schutjes1, P. Rindt2, K.J. Loring1,3, J. Vernimmen1 and the Magnum-PSI team1
1

2

Dutch Institute For Fundamental Energy Research (DIFFER)
De Zaale 20, 5612 AJ Eindhoven, The Netherlands
First author email: I.G.J.Classen@differ.nl

Science and Technology of Nuclear Fusion Group, Eindhoven University of Technology, Eindhoven,
Netherlands
3

Stanford University, Palo Alto, California, United States of America

The biggest challenge in the development of a reliable fusion reactor is the handling of large
heat and particle loads on the reactor wall. To solve this heat exhaust problem, two different
approaches can be taken:
1) The development of advanced reactor wall concepts that are capable of surviving the heat
fluxes in future reactors, for example using liquid metal plasma facing components.
2) Developing plasma scenarios that greatly mitigate the fluxes before they hit the reactor wall,
most notably detachment. Key to understanding detachment is the interaction of the plasma
with a background of neutral particles in the divertor region.
Linear plasma devices are often used for studying the various aspects of the heat exhaustproblem, as they offer divertor relevant conditions in a controlled, accessible and welldiagnosed environment. Currently, two linear devices are operational at DIFFER: Magnum-PSI(see fig. 1) and UPP. Magnum-PSI is
the main plasma facility at DIFFER,
capable of producing reactor relevant
heat and particle fluxes. The smaller
UPP device, operational since 2021,
will enable operando ion beam
analysis of the plasma target, and is avaluable testbed for new diagnostics.
A third linear device, LiMeS-PSI, isunder development. LiMeS-PSI will
Fig. 1: The Magnum-PSI linear device [1]be dedicated to testing liquid metal
simulates the divertor conditions of future
divertor concepts.
fusion reactors.
In this talk a selection of DIFFER linear device studies will be presented, all aiming at
developing solutions to the heat exhaust problem. These studies include:- Material testing of conventional Tungsten plasma facing components [2];- Development of liquid metal divertor concepts, including vapor shielding [3,4];- Detachment physics and divertor plasma characterization studies [5];- Development of active spectroscopy methods to diagnose the neutrals in the divertor.
[1] H. van Eck et al., Fusion Eng. Des. 142 (2019) 26–32[2] T.W. Morgan et al., Phys. Scr. T171 (2020) 014065[3] G.G. van Eden et al., Phys. Rev. Lett. 116 (2016) 135002[4] P. Rindt et al., Nucl. Fusion 59 (2019) 056003[5] J. van den Berg et al., Nuclear Fusion 61 (2021) 096007

PSLO-KN-5

Review on DiPS-2 as a Linear Plasma Device:
Source, Diagnostics, Physics and PMI
Kyu-Sun Chung1 and APLers2
1

2

Department of Electrical Engineering, Hanyang University
222, Wangsimni-ro, Seongdong-gu, Seoul 04763, Korea
kschung@hanyang.ac.kr

Former Members of Applied Plasma Laboratory of Hanyang University

DiPS-2 is a linear plasma device for simulating divertor and scrape-off layer (SOL) plasmas,
which has been evolved as the following: (1) Diversified Plasma Simulator (DiPS) has beendeveloped for simulations of divertor and space plasmas with various electric probes, such as
single, triple, and Mach probes and gridded energy analyzer. DiPS consists of two major parts:
a divertor plasma simulator with a LaB6 DC plasma source and a space plasma simulator witha helicon RF plasma source; (2) Divertor Plasma Simulator-1 (DiPS-1) is a part of DiPS with
only a LaB6 cathode, where a low-power laser-induced fluorescence (LIF) is added and more
electric probe diagnostics are augmented. It is dedicated only for fusion edge and divertor
plasmas; and (3) Divertor Plasma Simulator-2 (DiPS-2) has been modified from the DiPS-1 byadding a magnetic nozzle with a limiter structure. DiPS-2 has a plasma source with a 4-inch
LaB6 cathode, the same source as DiPS-1, and it is focused on plasma-material interactions(PMIs) and the development of various diagnostics such as LIF, laser Thomson scattering (LTS),
and laser photo-detachment (LPD) along with various electric probes.
Although DiPS-2 could not generate ions with high temperature and toroidicity with muchless power density compared to toroidal devices, it has been used for a few fusion-relevant
physics experiments, including edge localized mode (ELM) simulation and edge transport ofdiffusion and convection: (1) an ELM simulation has been performed by modulating themagnetic field relevant to the pressure modulation of toroidal devices; and (2) the diffusion
coefficients of free and bounded presheaths have been measured by simulating divertor or
limiter transport. Moreover, the convection of the filament or the bubble expansion to the firstwall of toroidal devices has been analyzed. PMIs have also been studied in terms of thefollowing elements or processes: (1) boronizations, both for dust interactions with the surface
chamber (DiSC) and KSTAR device, are analyzed; and (2) tungsten as a divertor-tile material
is analyzed via laser ELM simulations in terms of dust generation and surface modification.

Schematic diagram of the DiPS-2, where LaB6 plasma source is on the left side, a magnetic nozzle islocated in the middle, and DiSC is augmented on the right side.

DX-I-1

Plasma Fundamental Research Activities based on Atomic andMolecular Data in Korea Institute of Fusion Energy
Mi-Young Song1*, Young Choon Park1, Heechol Choi1, Yeunsoo Park1, Young-Rock, Choi1, Dae-Chul
Kim1, Jongsik Kim1, Yonghyun Kim1, Hyonu Chang1, Nidhi Sinha1, Swati Bharti1, HyunYeong Lee1 ,Jun-Hyoung Park1, Sun Min Han1

1

Institute of Plasma Technology, Korea Institute of Fusion Energy, 37 Dongjangsan-ro
Gunsan, Rep. of Korea

Corresponding Author e-mail: mysong@kfe.re.kr*

Through this opportunity, we would like to introduce the foundamental research of lowtemperature plasma at KFE.
In recent years, we have utilized our research base to study the chemical and physical propertiesof candidate gases for the development of new alternative gases.
In particular, the properties of low GWP process gases in the semiconductor process werestudied using the density functional theory DFT (wB97X-D/aug-cc-pVTZ) calculation using
the Gaussian 09 program. In addition, the scattering cross-section by the electron collision gas
was calculated using the R-matrix method.
Standard reference data for the spectral characteristics of the visible light region in ICP
13.56MHz argon plasma and nitrogen plasma were developed, and through this, wavelengths
with high correlation with spectral signals and plasma temperature and density were secured.
In addition, the relationship between the atomic and molecular state characteristics of theplasma generation gas and the characteristics in the plasma was identified through themeasurement of neutral species and ion species in CxFy plasma.
In addition, the International Data Evaluation Group has developed various scattering crosssection data sets for electron collisions with CH4,NF3, NxOy, and N2 molecules. It can be usedas basic data required for plasma analysis.
This work was supported by the R&D Program Plasma BigData ICT Convergence Technology
Research Project through the Korea Institute of Fusion Energy (KFE) funded by theGovernment, Republic of Korea.
REFERENCES:[1] Mi-Young Song, Hyuck Cho, Grzegorz P. Karwasz, Viatcheslav Kokoouline,
Jonathan Tennyson, J. Phys. Chem. Ref. Data 52, 023104 (2023)[2] Heechol Choi, Young Choon Park, Yeon-Ho Im, Deuk-Chul Kwon and Sang-Young
Chung, Plasma Chemistry and Plasma Processing, 43, 47-66, 2023
[3] Nidhi Sinha, Heechol Choi, Mi-Young Song, Hyun-Jae Jang , Yeon-Ho Oh, Ki-Dong Song,
Computational and Theoretical Chemistry 1225 , 114159, 2023

DX-I-2

Multi-scale deep learning for estimating horizontal velocity fields on thesolar surface
Ryohtaroh T. Ishikawa1
National Institute for Fusion Science,
322-6 Oroshi-cho, Toki, GIFU 509-5292, Japan
ishikawa.ryohtaro@nifs.ac.jp
1

The dynamics on the solar surface are governed by thermally driven convection. Thisin turn produces cellular patterns that are observed in visible light continuum images. The
bright areas with hot upflows are surrounded by darker and cooler downflows. The
turbulent nature of the surface convection inherently creates flow structures that aresmaller than the typical size of the convection.
We can obtain the line-of-sight (LOS) component of the flow velocities by spectroscopic
observation via the Doppler effect. Conversely, there are no direct methods for observing
the components perpendicular to the LOS to date. These components correspond to thehorizontal velocity on the solar surface in disk center observations. There is a classicalmethod called Local Correlation Tracking (LCT) [1] to estimate the horizontal velocity from
intensity maps, but it has been pointed out that the LCT underestimates the velocity [2].
We developed a convolutional neural network that predicts the spatial distribution ofhorizontal velocity from the spatial and temporal variations of vertical velocity andtemperature [3]. This model includes multi-scale deep learning architectures: theconvolution layers have receptive fields of various sizes. This deep learning model is trainedwith numerical simulation data of the solar surface convection [4]. Moreover, we also
developed coherence spectrum that can evaluate the correlation between the output imageof the deep learning model and the original simulation data.
The multi-scale deep learning method successfully predicts the horizontal velocities.
The correlation coefficient between the output of our model and the simulation was 0.77
which is better than the accuracy of LCT. We also found that the coherence spectrum has
a strong dependence on the spatial scales; coherence is higher than 0.9 on large scales but it
rapidly decreases to less than 0.3 on smaller scales. This decrease in coherence seems tooccur near the energy injection scales that are comparable to the typical size of theconvective cells.

[1] L. J. November and G. W. Simon, The Astrophysical Journal, 333, 427 (1988)[2] M. Verma, M. Steffen, and C. Denker, Astronomy & Astrophysics, 555, A136 (2013)[3] R. T. Ishikawa, M. Nakata, Y. Katsukawa, Y. Masada, and T. L. Riethmüller, Astronomy& Astrophysics, 658, A142 (2022)[4] T. L. Riethmüller, et al., Astronomy & Astrophysics, 568, A13 (2013)

DX-I-3

Interpretable AI Supporting Scientists' Insight into Large-Scale Dynamics
Yoh-ichi Mototake
Graduate School of Social and Data Sciences, Hitotsubashi University,
Kunitachi-shi, Tokyo 186-8601, Japany.mototake@r.hit-u.ac.jp

I will introduce our efforts to elucidate the mechanism of large-scale dynamics using aframework of machine learning called interpretable AI. In recent years, machine learningmodels such as deep neural networks, which are widely used for their high performance,
generally become black boxes that are difficult to interpret. In this talk, I explain two
machine learning frameworks that reduce the large-scale system to a small-scale
Hamiltonian system using a neural network, and, by interpreting the obtained neuralnetworks model, reveal the system's mechanism.
The first framework is a framework to support the construction of reduced coordinates of asystem using trained neural networks [1]. In this framework, a neural network that haslearned the time series data of a large-scale system estimates the continuous symmetry of
the system in a given reduced coordinate system (Fig). In Hamiltonian systems, thecontinuous symmetry of the system corresponds to conserved quantities, so the goodness of
the reduced coordinate system can be evaluated in a physically interpretable form. I willshow that this method can be used to support the construction of a reduced model of quasistable states of collective motion of fishes, which is a kind of active matter.
The other framework is for constructing reduced Hamiltonians using Hamiltonian neuralnetworks [2]. Hamiltonian neural networks can estimate corresponding Hamiltonians as
reduced models by taking reduced coordinate systems as inputs. Furthermore, combining
them with autoencoders makes it possible to simultaneously estimate the reduced
coordinate system and the reduced model by taking the original coordinate as input. By
analyzing the properties of the Hamiltonian obtained as a neural network, interpretable
information can be obtained. I introduce our trials of applying this framework to large-scale
systems such as magnetic domain
formation or fluid system.
In this talk, I will also introduce
some points to note when
extracting interpretable physics
information from neural networks
based on our empirical experience.
Along with these insights, I would
like to introduce the effectivenessandlimitationsofgeneralframeworks that support physics
Fig. Extraction of interpretable information from trained DNNs
research using neural networks.
[1] Y. Mototake, Phys. Rev. E 103, 033303 (2021).
[2] S. Greydanus, M. Dzamba, and J. Yosinski, Neurips 32 (2019).

GN-I-1

Plasma processing for diamond wafers
Hideaki Yamada
National Institute of Advance Industrial Science and Technology, Japan.
1-8-31 Midoriga-ooka, Ikeda, Osaka 563-8577, Japan.

Several material constants of diamond which are the best amongst competitive materials
have atracted reserchers to realize several wonderful applications in industry in addition tomechanical tools and gem stones. Diamond is one of the ultra-wide-bandgap materials, which
are expected to realize power devices with higher performance than those made of Si, SiC, andeven GaN. Quantum information of Nitrogen-Vacancy center in diamond can be controlled
under steaady state, which may realize future inromation technology and quantum sensing.
For such purposes, it is indispensable to establish the way to produce the wafers with
sufficent quality for each purposes under acceptable cost. The “man-made-diamond“ was firstly
reported by using high-pressure-high-temprature method [1]. Then, plasama CVD was foundto be another option to obtain diamond crystals artificially [2]. At present, mono-crystalline
diamond substrates with even more than 10millimeter square, which were homo-epitaciallygrown, are commercially available [3]. Hetero-epitaxial diamond with almost 4-inch diameter
was also reported [4]. Mosaic wafer is another opition to obtain homo-epitaxially grown inch
size wafer [5]. Figure 1 shows companies which produces CVD mono- and poly- crystalline
diamond raw material (colored in blue) and some products made of daimond (colored in red).
Most of them started their activity in this 20 years. For this progresses, development of plasma
CVD is indispensably important.
In this presentation, current state of the art of the plasma CVD for diamond growth isreviewed, which is followed by related R&D to develop techniques to realize diamond wafers
for above mentioned several purposes.

Fig. 1 Companies which produce diamond raw materials and products made of diamond.

References[1] F. P. Bundy, H. T. Hall, H. M. Strong, et al., Nature 176 (1955), 51.
[2] M. Kamo, Y. Sato, S. Matsumoto, and N. Setaka, J. Cryst. Growth 62 (1983) 642.
[3] EDP Corpolation, https://www.d-edp.jp/en/ (last accesed at Sep. 8, 2023).
[4] Diamond Foundry, https://diamondfoundry.com/ (last accesed at Sep. 8, 2023).
[5] H. Yamada, A. Chayahara, Y. Mokuno, et al., Appl. Phys. Lett. 104, 10 (2014) 102110.

GN-I-2

Nitrogen doped and undoped Ti3C2Tx/Co3O4 hybrid composites synthesis forapplication as anode materials in flexible Supercapacitor
A. Ali*,1) L.M.C.H.P. Nguyen1), Sosiawati Teke1), Y.S. Mok1)
1) Department of Chemical Engineering, Jeju National University, South Korea

Keywords: MXene, Co3O4, hybrid composites, doping, supercapacitor
Corresponding author*: adnanaligohar@gmail.com

Abstract
Freestanding and flexible electrodes are vital for the development of flexible and wearable devices that store energy.
But the significant trade-off between mechanical flexibility and electrode electrochemical performance limits the
fabrication of efficient energy storage systems. In this research, we report the synthesis of a nitrogen undoped anddoped hybrid composite made of 2D material i.e. Ti3C2Tx and Co3O4. Nitrogen doped hybrid composite is synthesized
by reacting it with Urea in a hydrothermal unit at 180°C for 18 hours. These hybrid composite materials werecharacterized by scanning electron microscopy (SEM) Energy Dispersive Spectroscopy and X-Ray Diffraction formorphology and phases analysis. Besides these Transmission electron microscopies (TEM) and X-ray Photoelectron
spectroscopy (XPS) were also done. For electrochemical analysis these hybrid composites materials were applied on
the 1 cm2 carbon cloth as active material (Working electrode). Their electrochemical i.e. cyclic voltammetry (CV),galvanic charge/discharge (GCD) and electrochemical impedance spectroscopy (EIS) were carried out in a threeelectrode set-up by immersing working electrode, counter electrode (Pt) and reference electrode (Ag/AgCl) in 1M
H2SO4 electrolyte. We have studied the effect of different weighted ratios of N-doped and undoped Ti3C2Tx/Co3O4
while doping while keeping the working electrode weight constant. Furthermore, we have studied the effect ofdifferent weighted ratios of N-doped and undoped Ti3C2Tx and Co3O4 nanoparticles and carried out the same set ofcharacterizations and analyzed as active material for applying as active material in supercapacitor.

Figure 1. Ti3C2Tx, N-doped and Co Doped Ti3C2Tx anode material deposited on CC for flexible supercapacitor

GN-I-3

Development of Plasma Catalysis System for Reducing the Emissions of
GHGs and Air Pollutants
Amir Machmud, and Moo Been Chang
Graduate Institute of Environmental Engineering, National Central University, No. 300, Zhongda Rd, Zhongli
District, Taoyuan City 32001, Taiwan
mbchang@ncuen.ncu.edu.tw

Plasma catalysis offers potential solutions for reducing the emissions of greenhousegases (GHGs) and air pollutants. This emerging technology shows promise in improving
current technologies across various applications. The advantages of plasma catalysis stem fromits capability to combine the high selectivity of catalyst with the reactivity of plasma [1].
Dielectric barrier discharge is commonly used as a plasma source for this application, operating
mainly under a filamentary regime where millions of microdischarges occur throughout thereactor with spatial and temporal non-uniformity. Recent studies have heavily focused onunderstanding these mechanisms and applying them effectively. Consequently, significant
research efforts have focused on exploring the mechanisms and applications of plasma catalysis.
A multitude of comprehensive reviews have been published over the years covering various
aspects including specific applications such as: NOx abatment, VOC abatment, PFC(perflurocarbon) abatment, and CO2 conversion, or highlighting the importance of modelingand simulation to enhance our understanding of this field [2-4]. Despite gaining considerable
interest for its diverse range of applications, vast majority of tests were conducted on alaboratory size. Considerable progress is being made in gaining an understanding of the
intricacies of the mechanism of plasma catalysis, and this is significantly assisted by thetheoretical and computational studies. In order to maximize the potential of plasma catalysis, it
is essential to harness its distinctive attributes such as simplified catalyst preparation, rapid
response times, low-temperature operation, and the synergistic effects between plasma andcatalysis. These unique features offer numerous advantages that can be leveraged in various
environmental applications. In this talk, several possible strategies to enhance the effectivenessand energy efficiency of plasma catalysis will be presented and discussed, i.e., (i) aligning thepower supply with the reactor, (ii) optimizing and adopting suitable catalysts, (iii) utilizing
computer-aided investigation of reaction mechanisms, and (iv) exploring potential pathways
for achieving high activity and selectivity.
[1] H. H. Kim, Y. Teramoto, A. Ogata, H. Takagi, and T. Nanba, Plasma Chem. Plasma Process.,
36, 45-72, (2016).
[2] X. Tu, J. C. Whitehead, and T. Nozaki, (Eds.). Plasma Catalysis: Fundamentals andApplications. (Berlin, Springer, 2019).
[3] H.L. Chen, H.M. Lee, S.H. Chen, Y. Chao, and M.B. Chang,. Appl. Catal. B, 85, 1-9, (2008).
[4] H.L. Chen, H.M. Lee, S.H. Chen, M.B. Chang, S.J. Yu, and S.N. Li,. Environ. Sci. Technol.
43, 2216-2227, (2009).

WFPP-I-4

Gradient-descent-method Analysis of Mie-scattering Ellipsometry during
Fine-particle Growth in Plasma
Yasuaki Hayashi and Akito Miya
Yamato University
Katayama, Suita, Osaka 564-0082, Japanhayashi.y@yamato-u.ac.jp

Mie-scatterig ellipsometry had been developed for the analysis of growth of fine particles
in plasmas [1-3]. It can analyze not only the size of fine partciles but the growth process andother physical phenomena about fine particles suspended in space such as plasma. In Miescatterig ellipsometry, analogous to thin film ellipsometry, the parameter angles Ψ and Δ aredefined by the ratio of the scattering amplitude function of a parallel polarization component,
Sp, in scattering plane and to that of a perpendicular one , Ss, astan Ψ・e j Δ =

𝑆𝑝
𝑆𝑠

.

Those two amplitude functions are calculated for a single or monodisperse spherical fineparticles by the Mie scattering theory. For polydisperse fine particles, Ψ and Δ are calculated
through the four Stokes parameters [1,3].
The growth process of fine partciles are analyzed by the comparison correspondence
between experimental and calculated results. Many unknown variables, such as particle size,
size-distribution, refractive index, scattering angle, as well as the azimuth adjustment errors ofpolarizer and analyzer, are related to the change of Ψ and Δ during particle growth. In order todetermine these multiple unknown variables, the machine learning method is a powerful
analytical method.
We have carried out the analysis of variation of Ψ and Δ during fine-particle growth using
regression analysis method as gradien-descent-method. Figure 1 shows an experimental resultof variation of Ψ and Δ during carbon fine particle growth in a methan plasma. The result of
the analysis revealed that the partcile size dispersion decreased with growth. It suggests thatfine parcicles grew by coating of carbon films on smaller ultra-fine particles.

[1] Y. Hayashi and K. Tachibana, Jpn. J. Appl. Phys.
33 (1994) L476.
[2] Y. Hayashi and K. Tachibana, Jpn. J. Appl. Phys.
33 (1994) 4208.
[3] Y. Hayashi and A. Sanpei, Chap.1 in Ellipsometry,
INTECH, 2017.

Fig. 1: Variation of Ψ and Δ during
particle growth in a methan plasma.

WFPP-I-5

Analyses of Coulomb Crystals in Dusty Plasmas
under Gravity and Microgravity
Kazuo Takahashi
Faculty of Electrical Engineering and Electronics, Kyoto Institute of Technology
Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
takahash@kit.jp

Coulomb crystals of dusty plasmas have been investigated by projects utilizing facilities
under microgravity for the past 20 years. An European Space Agency project of PK-4 has beenworking on the International Space Station since 2014. The apparatus of PK-4 enables toanalyze dynamics of dust particles in a cylindrical discharge plasma. The author is engaging inexperiments of the PK-4 on the ground and parabolic flights. Figure 1 shows the structures of
Coulomb crystal in detail, which have been obtained in ground-based experiments [1]. In acylindrical discharge plasma (Ar, 33 Pa, 700 Vp-p at 1 kHz), spatial distribution of dust particles
formed a cylinder with cross section of ellipse. Lower part of the cylinder consists of layers
including the hexagonal closed-packing structure, which clearly appears in the region of 2 < y< 4 mm. The closed-packing structure around center of the cylinder indicates that compressive
force toward to center confines the dust particles. Furthermore, outline of the cross section is
not identical to potential contour of the plasma without dust particles in the cylindrical discharge,
which the dust particles produce potential to confine themselves by self-consistent interaction
with the plasma. A structure of liner chains formed under microgravity will be discussed in thepresentation.
[1] Kazuo Takahashi and Hiroo Totsuji, IEEE Trans. Plasma Sci. 47, 4213 (2019).

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Fig. 1: Coordinates of dust particles in a cylindrical discharge plasma [1].

Topic number 6

etherlands

Highlystrength
Sensitive Electric
Vector Measurements
que for electric fieldandFieldfluctuation
Using an Optically Trapped Fine Particle
ts in plasma using a fine particle
M. Shiratani1, T. Sato1, K. Kamataki1 , S. W. Fitriani1，K. Tomita2,
1
1
1
P. Yiming2, D.1 Yamashita1, N. Yamashita
1 , N. Itagaki , and K. Koga

aki1 ,K. Tomita2, P. Yiming , D. Yamashita ,1,3 School of Information Science and1 Electrical Engineering, Kyushu University,
Graduate
N. Itagaki1, K. Koga
and Motooka
M. Shiratani
744, Nishi-Ku, Fukuoka 819-0395, Japan1

P

siratani@ed.kyushu-u.ac.jp

ormation Science and ElectricalGraduate
Engineering,Japan
School of Engineering, Hokkaido University,
Hokkaido University, JapanKita 8, Nishi 5, Kita-ku, Sapporo, Hokkaido, 060-0808 Japanl Institutes for Natural Sciences, Japan2

2

In low pressure processing plasmas, ions impinging on substrates often play key roles in theprocesses.
Ions sheath
are accelerates
electricfield
in pre-sheathand sheath before reaching
electric fieldplasma
vectorin plasmaregionbyby
a fineparticletrappedsubstrate.
kinetic energy
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ions are predominantly determined
results show
this Therefore,
measurement
methodhas a angle
highof sensitivity
by the electric field there. Especially, information on electric field and its fluctuation in aon (micro meterorder).
directionparallel to electrode surface are important, whereas it is difficult to obtain theinformation because electric field parallel to electrode surface is much smaller than thatperpendicular
to electrodesurface.
(horizontal
balance)+! ," = -"#$_" , and (vertical balance)Toobtainsuch
information,
here we have developed a method of electric field vector
acture micro- ). = +! ,& +-"#$_& , where+!particle
is the[1,particle
charge,measurements using an optically trapped fine2]. The electricfield).
vector is deducedent of electricfrom force
exertedthe,fine
particle.
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because of
and
are
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strengthofhorizontal
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ce in plasmazero method
as electric
well as a field,
high spatial
resolutionof theareorder
20 µm.ofFigure
vertical-"#$_"
and -"#$_&
theof force
the 1 shows anexampleoftwodimensional
profileofelectric
field
near
the
plasma-sheathboundary
using anving plasma laser on the particle, respectively. andwere"#$_" trapped"#$_&with laser tweezers. Thechanges andacrylic fine particle of 10, 15, 18, 20 µm in diameter, opticallyuniqueobtainedadvantage fromof the methodistomeasuresimultaneously
high
was 8000 V/man ray optical model [2], and +Ez! aroundnt impact ontogether with low Er below 20 V/m as well as their fluctuation.
deducedfrom Orbital Motion Limited(OML) model
work was partly supported by JSPF KAKENHI (Grant No. JP20H00142) and JSPSo micro- and Thisconsideringcollision[3].
Programion(GrantNo. JPJSCCA2019002).
hly sensitiveCore-to-Corec field. The
elds strength
rticle trapped

(a)

(b)

ent setup. A-illumination
sh grounded
1. Twodimensional
electric field
distributions(a) electric field perpendiculartoe, which was Figure
Figs.2Two
dimensional
electric
fieldof distributionsofsurface, Ez and (b)electric field parallel to electrode surface, Er.
(a) ,electrodeThe point at& and (b) ," .
Ar 60 Pa, 13.56 MHz rf parallel plate discharge plasma, 10 W.
the sapphire 3 Results and Discussion
Ito, et al., J. Phys. Conf. Ser. 518, 012017 (2014).
cy voltage of[1] T. Bychanging the particle size (= gravity force), the[2] M. Shiratani, et al., Mater. Sci. Forum 879, 1772 (2017).
es to generate measurement region in the plasma sheath can be selected18, 20 µm in and expanded. Figures 2 show 2D distributions of ,& andced into the (b)," . These results show that decreased from the plasma
ath boundary sheath region to the bulk of the plasmathe effect of ion drage particle was force. We will discuss the detail at the conference.
When it was

WFPP-I-6

PSLO-KN-6

Laser-induced breakdown spectroscopy for wall diagnosis in nuclear fusion
devices
Hongbin Ding
Key Laboratory of Materials Modification by Laser, Ion and Electron Beams,
Chinese Ministry of Education, School of Physics,
Dalian University of Technology, Dalian, 116024, P.R. China
hding@dlut.edu.cn

In recent years, Laser-Induced Breakdown Spectroscopy (LIBS) has been developed for
diagnosis of the co-deposition of impurities, fuel retention and wall conditioning on the firstwall in fusion devices such as EAST, HL-2A[1] and KSTAR tokamaks[2] as well as W7X
stellarator[3]. The main challenges faced by the LIBS diagnosis approach in fusion wall
elemental analysis arise from two issues: firstly, LIBS spectral intensity is strongly affectedby laser-plasma interaction such as the prompt electrons emissions, plasma shielding, charge
separation, plasma sheath, self-absorption in vacuum environment such like Tokamaks;
secondly, the matrix effect arising from the hardness and temperature of the substrate sample,
which is due to laser-target interaction such as the nonlinear features in the different ablation
regions: optical, thermal, phase-explosion; To achieve high accuracy of LIBS analysis, thelaser-plasma interaction and the fluctuation of transient plasma parameters, which affect the
LIBS stability and analysis accuracy, must be eliminated or reduced by the hardware or thealgorithm software. So far, various approaches to improve LIBS signal strength and theplasma stability have been investigated in our team and others, including
polarization-resolution constraint, magnetic field constraint, double-pulse and DC-dischargeenhancement using micro-, nano-, pico- and femo-second lasers. For understanding matrix
effect, recently the influence of the chemical sates, hardness, conductivity and temperature of
the substrate sample on LIBS have been investigated. Above-mentioned, an in-situ
endoscoped LIBS system has been successfully developed for the wall diagnosis study in
EAST tokamak. The results show optimistic prospects and more details will be discussed inthis forum.
[1] C.Li et al., Frontiers of Physics, 11,114214(2016)[2] L.Sun, et al., Nuclear Materials and Energy, 31, 101174(2022)[3] C.Li et al., Physica Scripta, T170, 014004 (2020)

PSLO-I-2

Development of Plasma Application Technology in IPT-KFE
Yong Sup Choi1
1

Institute of Plasma Technology, Korea institute of Fusion Energy
37 Dongjangsan-ro, Gunsan, 54004, Korea
yschoi@kfe.re.kr

Plasma Technology is widely used in various fields such as semiconductor, display, particle
processing, surface modification, environment, bio, agriculture, and so on.
The Korean government-funded Institute of Plasma Technology at Korea institute of Fusion
Energy(IPT-KFE) is developing the fundamental, core, and convergence technologies ofplasma. The fundamental plasma technologies are cross section measurement and calculation,
plasma material interaction, plasma modeling and simulation, and diagnostics and control. The
core technology is development of new type plasma sources and innovation in applied plasma
sources. The convergence technology is industrial applications of core technology.
Current research activities and applications of technologies will be presented, including
plasma farming, semiconductor and display application, waste treatment, and so on.

PSLO-O-1

Surface morphology and grain structure changes induced by helium ion
implantation and subsequent thermal annealing
Jia-Guan Peng*, Long Cheng, Yue Yuan, and Guang-Hong Lu
School of Physics, Beihang University,
Beijing 100191, China
peng1919@buaa.edu.cn

Plasma-wall interaction (PWI) originated from high-flux plasma irradiation together withhigh heats load has been recognized as a critical concern for ITER which could impact both
plasma operation and divertor component lifetime. Helium (He) is one of the main impurities
in fusion edge plasma. In previous work, distinct changes in the surface morphology of tungsten(W) were observed under He plasma irradiation with a low incident energy of 80 eV and a low
fluence of 4×1024 m-2 at a high surface temperature of 1400 K [1]. After He plasma irradiation,
it was also found that He nano-bubbles could retard recrystallization through the Zener dragforce during annealing [2]. He could also be in bulk W in ways of energetic He ion implantation
or transmutation. It has been found that the irradiation of W by He ion with an incident energy
less than 100 keV can induce complex surface morphology changes [3]. Despite these findings,
precise alterations in grain structure and surface morphology resulting from the effect of He
and heat treatment remain unclear. In this work, the effect is investigated by using He ion
implantation and subsequent thermal annealing.
Mirror-polished rolled W samples were exposed to He ions with energies ranging from 10
keV to 100 keV and ion fluences ranging from 1019 m-2 to 1022 m-2 followed by subsequentannealing at temperatures ranging from 1373 K to 1973 K. The results indicate that a low
concentration of 40 appm He in W could significantly retard the recrystallization process in W.
Moreover, the grain boundary (GB) motion transitions from shear-coupled migration to puresliding migration at a higher He concentration. No distinct surface morphology change wasfound right after ion irradiation. However, when W samples were exposed to fluence larger than
1×1021 m-2 and annealing at temperatures above 1473 K, a distinctive wave-like structure,measuring 3 nm in height, emerged in {111}-oriented grains, while {100}- and {110}-oriented
grains exhibited no noticeable changes. Underlying mechanisms of the microstructure evolution
are discussed based on ion channeling effects, He-vacancy interactions and dislocation looppunching.
The results show that helium ion implantation retards grain boundary migration andinduces surface morphology evolution during the annealing process. This contributes tounderstand the effects of helium on tungsten in ITER divertor. The temperature window ofdivertor operation might be enlarged by He in W.

[1] C.M. Parish, H. Hijazi, H.M. Meyer, F.W. Feyer, Acta Mater. 62 (1) (2014).
[2] Guo W, Cheng L, De Temmerman G, Yuan Y, Lu G.-H, Nucl. Fusion (2018).
[3] Y. Ueda, H. Peng, H. Lee, N. Ohno, S. Kajita, J. Nucl. Mater. 442 (1–3) (2013).

PSLO-O-2

MD simulation of the interaction between hydrogen and helium bubble inbcc iron
Ze Chen*, Zhengyang Ming, Chao Yin, Shifeng Mao, and Minyou Ye
School of Nuclear Science and Technology, University of Science and Technology of China
Anhui, Hefei 230026, China
zechen@ustc.edu.cn

It is of vital importance to understand the interaction between hydrogen (H) and helium(He) bubbles in reduced activation ferritic-martensitic (RAFM) steels for future fusion reactors.
This work used molecular dynamics (MD) simulations to evaluate the H retention behavior ofnano-sized spherical/cubic He bubbles, both of which have been observed in experiments. For
spherical He bubbles, the effect of He-to-vacancy (He/V) ratio, bubble size, H concentration,and temperature on the H retention were studied in detail. The simulation results suggest thatH prefers to reside at the bubble interface, with only a small fraction of trapped H inside thebubble. H2 molecules were observed inside the He bubbles and the relation between H2formation and the He/V ratio within the bubble is discussed. The binding energy of atomic H
to a 2 nm He bubble with a He/V ratio of 1.0 was calculated to be 0.73 eV by molecular statics(MS). Besides, for cubic He bubbles, the dependence of bubble orientation ((110) and (100))on H trapping behavior was also investigated with the same He/V ratio of 1.0, size of 6 nm, andat the temperature of 923 K. Results indicated that the (110) bubble was more stable with lesstrapped H atoms than the (100) one. H prefers to be trapped at the edge regions instead of facecenter regions for both situations, which can be explained by the local stress distribution near
the bubble. The difference of H trapping behavior between cubic bubbles and cubic voids was
also discussed.

DX-I-4

Data Assimilation in Semiconductor Crystal Growth: Chemical Reaction
Network Modeling
Akira Kusaba
Research Institute for Applied Mechanics (RIAM), Kyushu University,
Kasuga, Fukuoka 816-8580, Japankusaba@riam.kyushu-u.ac.jp

In semiconductor crystal growth, accurate modeling of vapor phase chemical reactions
is crucial to control impurity concentrations. In general, those reactions form a complex
network. The reaction rate constants for each reaction have been determined by firstprinciples calculations based on density functional theory (DFT) and transition state theory(TST). This is due to the difficulty of in situ measurement experiments in a reactor. However,
the rate constants determined by calculations are often not quantitative enough to meet therequirement of concentration control in semiconductor engineering.
On the other hand, recent advances in measurement technology have made it possible
to obtain concentrations of chemical species that could not be measured before. But it isstill impossible to determine rate constants only from experimental data. Therefore, it isnecessary to make good use of both computational and experimental data. In this researcharea, experimental data are generally more accurate as absolute values than computational
data. Conversely, computational data are generally more comprehensive than experimental
data. Thus, fitting to experimental data needs to be performed while preserving the trendof computational data.
Such an approach corresponds tothe well-known data assimilation inmeteorology. This study shows thatsuch tuning of rate constants ispossible simply by multi-objective
optimization, rather than by using
advanced statistical theory. In
addition, the importance of reducing
the size of reaction network toprevent overfitting is mentioned(Fig. 1). In the forum, more details
will be presented, focusing on theFig. 1: Reduced reaction network in GaN MOVPE.
methodology.

[1] A. Kusaba, S. Nitta, K. Shiraishi, T. Kuboyama, and Y. Kangawa, Appl. Phys. Lett., 121,
162101 (2022).

DX-I-5

A new approach to mixed-domain and higher-order dependence modeling
Keisuke Yano1 and Tomonari Sei2
The Institute of Statistical Mathematics
Micori cho, Tachikawa City, Tokyo, 190-8562, Japan
yano@ism.ac.jp
1

The University of Tokyo,
Bunkyo-ku, Hongo, Tokyo 113-8656, Japan
sei@mist.i.u-tokyo.ac.jp
2

In data analysis, we frequently encounter mixed-domain data. This refers tomultivariate data spanning various domains such as real values, categorical values, manifold
values, and functional values. Categorical variables denote qualitative data, while manifoldvalued variables typically manifest as directional or axial data. On the other hand,functional variables can be observed in forms such as power spectra.
In this presentation, we will introduce the minimum information dependence model[1]. This statistical model is tailored to analyze potential higher-order dependencies inmixed-domain data. We will highlight its utility through its application in the ecologicalstudy of penguins [2] and in the analysis of earthquake catalogs [3].

Figure 1: (a) Application to the ecological study of penguins for extracting the first andthe second order dependencies; (b) The map of rupture patterns of 158 earthquakes that
occurred in Japan during the period from January 1st, 2021 to December 8th, 2021 (c)Extracted dependence between the rupture patterns and the source depths.
[1] T. Sei and K. Yano, Minimum information dependence modeling for arbitrary productspaces, arXiv:2206.06792[2] Horst, A. M., Hill, A. P. and Gorman, K. B. (2020). palmerpenguins: Palmer Archipelago(Antarctica) penguin data R package version 0.1.0.
[3] Japan Meteorological Agency (2022). The seismological bulletin of Japan.
https://www.data.jma.go.jp/svd/eqev/data/bulletin/index e.html.

DX-I-6

Monolayer Graphene, an ideal material for exploring out-of-equilibrium
phenomena involved in plasma-surface interactions
Pierre Vinchon1, Luc Stafford2 and Satoshi Hamaguchi1
1Center for Atomic and Molecular Technologies, Osaka University
2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
vinchon@ppl.eng.osaka-u.ac.jp

2

Département de Physique, Université de Montréal, Montréal, QC H2V 0B3, Canada

With the ever-decrease in semiconductor devices dimensions, the precise understanding ofplasma-surface interactions becomes crucial. It is especially necessary to study how lowpressure plasma can generate defects despite the low-energy ions which can be used in certain
processes. Upon contact with the sample, plasma excited species generate out-of-equilibrium
phenomena on surfaces, of which influences are difficult to quantify. Furthermore, synergistic
phenomena can arise with the simultaneous irradiations of the sample by other plasma-excitedspecies such as metastable and VUV photons. These effects are often invoked but rarely
understood. As a result, a mechanistic understanding of plasma-surface interactions involving
all excited species remains a challenge.
Since its experimental discovery in 2004, tremendous research effort worldwide has been
focused on monolayer graphene to harness its remarkable properties. There are now numerous
characterization methods that enable a precise understanding of its structure. Raman
spectroscopy is particularly successful in providing a clear view of defect concentration andnature without altering the graphene state. Graphene will be particularly affected by any surface
treatment which makes it ideal for the observation of phenomena affecting the extreme surface.
It has been shown that low-pressure Argon plasma irradiation of graphene induces asignificant amount of defects despite the ultralow energy ions (~12 eV). This is even more
remarkable considering that the threshold energy to generate defects in graphene is wellestablished at 18-22 eV [1]. There is reason to believe that ion neutralization to the surface
may contribute to defect generation [2]. On the other hand, Argon metastable influence, often
overlooked for 3D materials treatment, has been observed to have a non-negligible influenceon graphene, promoting vacancies migration and nucleation [3]. Both ions and metastable aresuspected to generate transient hot electrons and holes in graphene, leading to out-ofequilibrium physics in graphene.
We will present how Molecular Dynamics simulations can support experiments involving
graphene, enabling a better understanding of mechanisms that are in play at extreme surfaces
during plasma-surface interactions. This would also contribute to shedding light on synergistic
effects related to the combined influence of plasma-excited species. More generally, it isexpected that experiments conducted with monolayer graphene could benefit other plasma
processes in which atomic control is required.

[1]
[2]
[3]

F. Banhart, J. Kotakoski, and A. V. Krasheninnikov, Structural Defects in Graphene,
ACS Nano 5, 26 (2011).
P. Vinchon, X. Glad, G. Robert Bigras, R. Martel, and L. Stafford, Preferential SelfHealing at Grain Boundaries in Plasma-Treated Graphene, Nat Mater 20, 49 (2021).
P. Vinchon, X. Glad, G. R. Bigras, A. Sarkissian, R. Martel, and L. Stafford, Plasma–
Graphene Interactions: Combined Effects of Positive Ions, Vacuum-Ultraviolet
Photons, and Metastable Species, Journal of Physics D: Applied Physics 54, 295202(2021).

DX-I-7

Poly-diagnostics of a nanosecond He-based atmospheric plasma
Nikolay Britun, Michael K. T. Mo, Shih-Nan Hsiao, Masaru Hori
Center for Low-temperature Plasma Sciences, Furo, Chikusa, Nagoya 464-8603, Japan
britun@plasma.engg.nagoya-u.ac.jp

Discharges with pulse-on duration shorter than the glow-to-spark transition time normallypossess high degree of non-equilibrium, where the temperature of heavy gas particles (e.g. He,
Ar, N2, etc.) may be close to 300 K. The non-equilibrium regime in this case favours vibrational
kinetics and efficient plasma radical production. In turn, the burst pulse regime of plasma
operation may further increase molecular decomposition as well as the radical production.
This work deals with poly-diagnostic characterization of a ns- He-based plasma discharge[1], both in space and time. The study is targeted at various plasma parameters which aresparsely measured in literature (for same discharge). The optical emission, absorption and laserbased spectroscopy techniques are involved to our work in order to cover the dynamics ofemission lines and ionization wavefronts, the electron density, rotational, vibrational and gas
temperature, the evolution of He 2s 3S1 metastable state and electric field, as well as thedischarge performance toward molecular decomposition (CO2) and synthesis (NO).
Among the main results, it was shown that the rotational excitation of N2+ ions precedes theelectron excitation of the He (3p 3PJ) state at the pulse beginning [2], which is followed byelectron avalanche with density exceeding 51015 cm-3. The peak of the electric field (about 25
kV/cm) follows shortly after the electron avalanche [3]. At the same time, He 2s 3S1 metastablestate gets abruptly populated during the pulse with number density exceeding 1014 cm-3 [4]. The
typical evolution of the electron density, the discharge current and the population of He 3S1state are shown in Figure 1.
The efficiency of CO2 decomposition isfound very low at small CO2 admixtures in He,
being at the same time > 20% at high admixtures(CO2/He > 3%) [5]. Since the thermal decomposition pathway should be likely excluded inour case, such decomposition behaviour can beassociated with rather high electron temperature
at low CO2 admixtures, whereas at higher
admixtures the (lower) electron energy may be
predominantly channelized towards
thevibrational excitation of CO2 [6] also resulting ina higher energy efficiency.
The work is supported by the JSPS
KAKENHI Tokusui project (19H05462).
[1] V. Gamaleev et al., Rev. Sci. Instr. 93, 053503 (2022)[2] N. Britun et al., PSST, 31, 125012 (2022)[3] N. Britun et al., J. Appl. Phys., 133, 183303 (2023)[4] N. Britun et al., (2023) in preparation.
[5] N. Britun et al., (2023) in preparation.
[6] A. Fridman Plasma Chemistry, Cambridge University
Press (2005)

Fig. 1: The time-resolved evolution of
the electron density, He 3S1 density anddischarge current in the electrode gap.

GN-I-4

Application of Gliding Arc Plasma in Nitrogen fixation: Conversion of
Atmospheric Nitrogen into Nitro compounds
Avik Denra1, Young Sun Mok1,*
1

Department of Chemical Engineering, Jeju National University, Jeju 63243, Republic of Korea

Abstract
The substantial increase in the investigation of suitable ways for nitrogen fixation can be attributed
to the need for higher agricultural productivity. Moreover, the abundant nitrogen in the atmosphereis not directly accessible to the living organisms. Currently, the commercial method of N2 fixationis the Haber Bosch process for the conversion of N2 into ammonia. However, the requirement ofhigh amount of energy along with tons of CO2 production are some of the major drawbacks of thisprocess. This work implements the application of rotational gliding arc plasma to convert N2 into
nitro compounds. The generation of high energy electrons and radicals in the plasma mixture iseffective to convert N2 into Nitrogen oxides (NOx) in the presence of oxygen (O2). Herein, theeffect of various input parameters (inlet gas flow rate, applied power, inlet gas composition) on
the overall NOx yield were studied to investigate the optimum conditions for better energy
efficiency. The NOx generation for an inlet composition of 3:2 N2 to O2 ratio was found to behigher compared to 1:1 feed ratio. For practical applications, the effect of water content in the feed
was also investigated. The resultant NOx generated in the reactor was oxidized and dissolved into
water to form Nitric Acid (HNO3). Thus, this work demonstrates a sustainable pathway for
nitrogen fixation at atmospheric conditions.
Keywords: Rotational gliding arc plasma, N2 fixation, Non-thermal plasma, NOx generation.
* Correspondence: smokie@jejunu.ac.kr; Tel: +82-64-754-3682

GN-I-5

The Potential of a Simple Microplasma Reactor in Cobalt Oxide
Nanoparticle Synthesis.
Sosiawati Teke, Roshan Mangal Bhattarai, Avik Denra, Mai Cao Hoang Phuong Lan Nguyen,
Young Sun Mok*
Department of Chemical Engineering, Jeju National University, Jeju-63243, Republic of Korea.
corresponding author: smokie@jejunu.ac.kr

Cobalt oxide nanoparticles have gained widespread attention due to their unique properties,
including an increased surface area, heightened reactivity, and exceptional optical, electronic,
and magnetic attributes compared to their bulk
counterparts. To precisely control particle size,
traditional bottom-up synthesis in liquid media has
been favored. In this study, we exploit the capabilities
of microplasma technology for the production of
Co3O4 nanoparticles, eliminating the need forhazardous reducing agents while ensuring both
efficiency and cost-effectiveness. The resultant
nanoparticles were subjected to a thoroughFigure 1. Schematic diagram of the microplasma setup.
characterization
process
involving
UV-Visspectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), fieldemission scanning electron microscopy (FESEM), and transmission electron microscopy(TEM). Our findings demonstrate the successful synthesis of Co3O4 nanoparticles through theimplementation of microplasma technology.

GN-I-6

Sputter-Grown Size-Selected Nanocluster Synthesis:
Deposition and Characterization for Material Science
Masahiro Shibuta
Osaka Metropolitan University, 3-3-138, Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
shibuta@omu.ac.jp

High-temperature plasma, which is achieved by strong laser irradiation or ion sputtering,
provides an important field for the synthesis of new functional nanomaterials with a bottom-up
method. For example, C60 fullerene is first generated in vacuum plasma and extracted as afunctional chemical compound. After the discovery of C60, many researchers have exploredartificial nanoclusters (NCs) composed of a few to several tens of atoms exhibiting distinct
chemical functionalities to be used as nanomaterials in the next generation.
Here, I introduce several examples of atomically controlled NCs generated in the plasma
field implemented by a magnetron sputtering (MSP) technique (Fig. 1 left) [1], where the NCs
are deposited onto the substrate. In the MSP system, not only NCs with single atomic species(e.g. Agn[2], Aln[3]), but also binary NCs (XmYn) can be synthesized using alloy targets. Fig. 1
center shows the mass distribution of cationic NCs generated from a Ta-Si alloy target,
providing selective generation of Ta1Si16 NCs (m/z = 630). The selective formation originatesfrom both electronic and geometric factors, namely, an electron shell closure is satisfied with
68 e− at cationic species, and close-packed metal encapsulation is available with the Si16 cage
to be Ta@Si16+. The amount of NC flux reaches several nA as an ion current, whose generation
amount can fabricate “pure” Ta@Si16 film on a substrate with several 10 min. deposition time.
The NC film can be characterized using conventional methods in the field of materialscience. The X-ray photoelectron spectra for Si 2p and Ta 4f core levels indicate 1:16 atomic
ratio of the deposited NCs and their preferable +1 charge state on the substrate (Fig. 1 right).
Furthermore, it revealed that the favorable charge states and chemical stabilities of M@Si16
NCs can be tuned by changing the central metal atom (M = Lu, Hf, Ta (period 6), and V, Nb,
Ta (group 5)[4,5]. These systematic studies will open up new material science based on aperiodic table of NCs synthesized in the plasma field.

Ta@Si16+

Ion current

n=6 7 8 9 ・・・

Fig. 1: (left) MSP NC
deposition system,(center) Mass distributionof TamSin+ NCs and(right) XPS spectra of the
Ta@Si16 film.

TaSin+

100 pA (6×108 cluster/s)
n=12 ・・・

200

400

Sin+

600

n=13 ・・・

800

Ta2Sin+1000

Mass number (m/z)

References[1] H. Tsunoyama, M. Shibuta, et al., Acc. Chem. Res. 51, 1735 (2018)[2] K. Yamagiwa, M. Shibuta, A. Nakajima, ACS Nano 14, 2044 (2020).
[3] M. Shibuta, et al., Nat. Commun. 13, 1336 (2022).
[4] M. Shibuta, et al., J. Am. Chem. Soc. 137, 14015 (2015). Phys. Chem. C 120, 15265 (2016).
[5] M. Shibuta, et al., Commun. Chem. 1, 50 (2018). Phys. Chem. C 126, 4423 (2022).

GN-I-7

A microplasma-based approach for the growth of highly crystalline carbon
nanotubes
Takashi Tsuji1, Guohai Chen1, Yoshiki Shimizu1, Hajime Sakakita1, Kenji Hata, Don Futaba1,
Shunsuke Sakurai1
1

National Institute of Advanced Industrial Science and Technology (AIST)
1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan
takashi.tsuji@aist.go.jp

The synthesis of defect-free, highly crystalline carbon nanotubes (CNTs) is crucial to fully
harness the exceptional properties of this material. The primary methods for growing CNTs
include substrate-based growth and gas-phase growth. In substrate-based growth, CNTs aregrown from a dense array of catalyst nanoparticles on a substrate, allowing for the growth of
CNTs in high areal density. However, defects in the graphitic lattice occur due to stresscontrentration at the CNT-catalyst interface from the contact with adjacent CNTs [1]. In
contrast, gas-phase processes involve the growth of CNTs from catalyst nanoparticles “floating”
through the reactor chamber. While this method yields highly crystalline CNTs, the areal
density of the resulting CNTs is low, which limits its productivity. This is attributed to theagglomeration of catalyst nanoparticles at higher concentrations.
To address these challenges, I will discuss the development of a multi-step, gas-phase
synthesis reactor composed of a micro-plasma based nanoparticle generator, a precision carbon
feeding system, and a thermal reactor [2]. Each of these components are critical in generating
the high density flow of size-controlled catalyst nanoparticles, which can be used to grow highcrystalline single-walled carbon nanotubes. In short, catalyst particles, are formed by flowing
the catalyst precursor through a microplasma for decomposition and nucleation. Then, theformed nanoparticles are mixed with a carbon feedstock within a very short time (a few
milliseconds) after formation to modulate the level of agglomeration. Employing this approach,
the growth of catalyst particles is effectively constrained to a scale of several nanometers evenwith catalyst precursor concentrations higher than those typically used in conventional gasphase growth. Consequently, we could grow highly crystalline single-walled CNTs from thesesmall particles. Characterization of the crystallinity by far-infrared spectroscopy (FIR) showedthat the crystallinity is on par with arc-discharge synthesized CNTs.
We envision that the high-density aerosol growth of highly crystalline CNTs can beachieved through further enhancements in catalyst activity (ratio of particles growing CNTs tototal particles).
[1] T. Tsuji, G. Chen, T. Morimoto, Y. Shimizu, J. Kim, H. Sakakita, K. Hata, S. Sakurai, K.
Kobashi and D. N. Futaba: Nanomaterials 11, 3461 (2021).
[2] G. Chen, T. Tsuji, M. Yamada, J. He, Y. Shimizu, H. Sakakita, K. Hata, D. N. Futaba, S.
Sakurai: Chem. Eng. J. 444, 13664, (2022).

WFPP-I-7

Discharge Mode Transition Triggered by Three-Wave Couplingin Partially Magnetized Cross-Field Plasma
JongYoon Park1 and Jung Young Kim2†
12

Department of Nuclear Engineering, Seoul National University, Seoul 08826, Korea
jongblues@snu.ac.kr

Department of AI semiconductor Engineering, Korea University, Sejong 30019, Korea
juneyoungkim@korea.ac.kr

In this study, we discovered that the discharge mode transition in a partially magnetizedcross-field plasma originates from a three-wave coupling between azimuthally rotating largeand small-scale spokes and the radially propagating breathing mode. By examining thefrequency spectra and spectrograms of probe signals, we traced the simultaneous evolution of
the rotating spokes into a turbulent state and the excitation of the breathing mode as themagnetic field strength intensified. Bi-spectral analysis offers conclusive evidence of thenonlinear coupling between the turbulent large- and small-scale spokes and the breathing mode.
Significantly, the nonlinear spectral power transfer noted during the excitation of the breathingmode highlights an energy exchange among different modes. Ultimately, the radially
propagating breathing mode induces an oscillation in the discharge current, driving thedischarge mode transition.

WFPP-I-8

Non-neutral plasmas in Penning-Malmberg traps:
fundamental studies and applications
Massimiliano Romé
1 Department of Physics, University of Milano, and INFN-Milano, Italy

massimiliano.rome@mi.infn.it

Contrary to the more common neutral plasmas, the dynamics of non-neutral plasmas isdominated by the electric field of their net charge [1]. The simplest non-neutral plasmas arecomposed of a single charged species. As an important example of the use of single-species
plasmas, one can cite the CERN experiments aimed at the production and study of antihydrogen,where positron plasmas [2] and antiproton plasmas are confined in Penning-Malmberg traps(PMTs). Such traps use a strong axial magnetic field for radial confinement and an electrostatic
field for axial confinement; the latter is produced by biasing a series of electrically isolated,hollow cylindrical conductors aligned along the magnetic axis.
The plasma density and total particle number in PMTs can be controlled by applying
rotating electric fields at frequencies close to the azimuthal rotation frequency of the plasma,or by using evaporative techniques. The rotating fields are produced by applying suitablyphased oscillating potentials to azimuthally sectored electrodes, while an evaporative coolingis performed by lowering one of the potential barriers confining the plasma such that the mostenergetic particles escape axially [3,4].
From the point of view of basic physics, the analogy between the transverse dynamics of asingle-species plasma in a PMT and that of an incompressible, non-viscous 2D fluid [5] allows
to carry out investigations of fluid phenomena under carefully controlled conditions and inalmost ideal conditions. These experimental investigations, accompanied by related numericalinvestigations, help to shed light on the dynamic characteristics of fluid flow [6], ranging fromthe onset and decay of diocotron (Kelvin-Helmholtz) waves to the development of coherent
structures and turbulence, in conditions of free evolution or under the effect of an external
forcing [7,8].
Recents results [9,10] on the control and manipulation of the dynamics of a pure electron
plasma obtained experimentally in the PMT ELTRAP [11] operating at the University of
Milano, and numerically with 2D or 3D particle-in-cell numerical simulations [12] are reported.
[1] R. C. Davidson, Physics of Nonneutral Plasmas (World Scientific, 1990).
[2] J. R. Danielson, D. H. E. Dubin, R. G. Greaves, and C. M. Surko, Rev. Mod. Phys. 87, 247(2015).
[3] M. Ahmadi, et al. (ALPHA Collaboration), Phys. Rev. Lett. 120, 025001 (2018).
[4] J. Fajans and C. M. Surko, Phys. Plasmas 27, 030601 (2020).
[5] M. Romé and F. Lepreti, Eur. Phys. J. Plus 126, 38 (2011).
[6] M. Romé, S. Chen, and G. Maero, Plasma Sources Sci. Technol. 25, 035016 (2016).
[7] M. Romé, S. Chen, and G. Maero, Plasma Phys. Control. Fusion 59, 014036 (2017).
[8] M. Romé, S. Chen and G. Maero, AIP Conf. Proc. 1928, 020012 (2018)[9] M. Romé, G. Maero, N. Panzeri and R. Pozzoli, ECA Vol. 43C, P2.4003, Proceedings ofthe 46th EPS Conference on Plasma Physics (Milano, Italy, 2019).
[10] G. Maero, N. Panzeri, L. Patricelli, and M. Romé, submitted to J. Plasma Phys. (2023).
[11] M. Amoretti, G. Bettega, F. Cavaliere, M. Cavenago, F. De Luca, R. Pozzoli, and M. Romé,Rev. Sci. Instrum. 74, 3991 (2003).
[12] Yu. Tsidulko, R. Pozzoli and M. Romé, J. Comp. Phys. 209, 406 (2005).

WFPP-I-9

Plasma-assisted Mist CVD for Formationof 3D Nanostructured Zinc Oxide Thin Films
Kosuke Takenaka1, Susumu Toko1 and Yuichi Setsuhara1
1

Joining and Welding Research Institute, Osaka University, Ibaraki, Osaka, Japank_takenaka@jwri.osaka-u.ac.jp

Functional oxide materials are expected as a key materials for next generation electronics.
In particular, flexible devices with functional oxide thin films have attracted great attention fornext-generation FPDs and flexible solar cells. Flexible devices including semiconductor andtransparent conducting oxide (TCO) should be formed at a temperature lower than the glasstransition (softening) temperature of polymer substrates.
Therefore, development offunctional thin film deposition at low temperatures is strongly desired for application to flexible
devices on polymer substrates. To overcome these problems in the low-temperature formationof functional thin films, plasma-assisted reactive processes using inductivity-coupled plasma(ICP) has been developed. In this study, functional oxide thin film deposition using plasmaenhanced chemical vapor deposition (CVD) have been studied. In advanced plasma-enhanced
CVD, plasma-assisted mist CVD have been developed. This system is combination of mist
CVD and plasma-assisted deposition. The surface morphology of the ZnO film deposited byplasma-assisted mist CVD shown by scanning electron microscopy (SEM) images shows that
the ZnO films were textured with round grains, which is attributed to the effect of the use of
mist with the precursor. [1,2] The plasma-assisted mist CVD is expected to be a film
formation method to control the surface structure of functional thin films.
Dropletvaporization behavior during plasma-assisted mist CVD of zinc oxide films was investigated.
The droplets injected into the plasma are vaporized by the heat flux from the plasma. It was
found that micrometric size droplets evaporate completely within several microseconds due toheat flux from the plasma. Moreover, owing to differences in vaporization rates, solid particles
were formed from some of the droplets during their passage through the plasma, but otherdroplets formed incomplete particles or remained as droplets due to incomplete evaporation.
Particles formed in the plasma and subsequently deposited on a substrate maintained theirshape.[2][1] K. Takenaka, Y. Okumura, and Y. Setsuhara, Jpn. J. Appl. Phys. 52 01AC11(2013)[2] K. Takenaka, and Y. Setsuhara, Plasma Sources Sci. Technol. 28, 065015 (2019).

WFPP-I-10

Evaluation of Carbon Nanoparticle Adhesion on Substrate Surface
Deposited by Plasma CVD*

Kazunori Koga1, Shinjiro Ono2, Manato Eri2, Takamasa Okumura1, Kunihiro Kamataki1,
Naoto Yamashita1, Naho Itagaki1, and Masaharu Shiratani1
1
Faculty of Information Science and Electrical Engineering, Kyushu University, 744 Motooka,
Nishi-ku, Fukuoka 819-0395, Japan1
Graduate School of Information Science and Electrical Engineering, Kyushu University, 744
Motooka, Nishi-ku, Fukuoka 819-0395, Japan*koga@ed.kyushu-u.ac.jp
Keywords: Plasma, Hydrogenated amorphous carbon, Carbon nanoparticle, Young’s Modulus
Nanoparticle deposition on a substrate is an important research topic for bottom-up
nanosystem fabrication using plasmas as well as nanoparticle synthesis. So far, we havestudied the growth of nanoparticles in plasma chemical vapor deposition (CVD) to realize size
and transport control [1-4], but information on the nanoparticles adhesion on the substrate islittle. Here we analyzed the adhesion status of carbon nanoparticles (CNPs) deposited on thesubstrate. We have successfully controlled the size of nanoparticles by plasma CVD [1, 2].
Based on the results, we produced CNPs of 20 nm in size using CH4+Ar plasma CVD. We
deposited CNPs on the surface of a hydrogenated amorphous carbon (a-C:H) film of 150 nm
in thickness. The projected area Cp of the deposited CNPs on the substrate was 10.9% of thetotal substrate area. The Cp was controlled by discharge duration for CNP production. We
analyzed mechanical characteristics of CNPs on substrate using a nanoindenter. We measured
the load-displacement characteristic of samples using a Berkovich indenter. The indentation
depth was set to 15 nm to obtain information on the a-C:H film without the influence of Si.
The hold time at maximum load was set to 1 s. For the sample without CNPs, the curves
showed a typical a-C:H thin film. The Young's modulus and hardness were 200 GPa and 26
GPa, respectively. For the sample with CNPs, the maximum load was about one-fifth of thatwithout CNPs and the modulus and hardness were 50 GPa and 3 GPa, respectively. The
differences in the curves are considered to be information that includes the mechanicalproperties of the nanoparticles as well as changes in the contact conditions of CNPs on thesubstrate during the indentation. Details will be discussed at the meeting.
[1] S.H. Hwang et al, Processes 9 (2021) 2.
[2] S.H. Hwang et al., Diam. Relat. Mater. 109 (2020) 108050.
[3] M. Shiratani et al., J. Phys. D: Appl. Phys 44 (2011) 174038.
[4] Y, Watanabe, J. Phys. D: Appl. Phys 39 (2006) R329.

WFPP-I-11

Contribution of Condensation and Coagulation for Nanoparticle Growth
in Modulated Induction Thermal Plasmas
Yasunori Tanaka1, Yurina Nagase1, Yusuke Nakano1, Tatsuo Ishijima1,
Shiori Sueyasu2, Shu Watanabe2, Keitaro Nakamura2
1

Kanazwawa University
Kakuma, Kanazawa, Ishikawa 920-1192, Japantanaka@ec.t.kanazawa-u.ac.j2

Research Center for Production and Technology, Nisshin Seifun Group Inc.,
Tsurugaoka 5-3-1, Fujimino 356-8511, Japan

Nanoparticles (NPs) have garnered significant attention due to their exceptionally highspecific surface area and distinctive physical and chemical properties. The demand forfunctional nanoparticles produced at high production rates has led us to develop an original andinnovative method: the Tandem-Type Modulated Induction Thermal Plasma (Tandem-MITP)
with Time-Controlled Feeding of Feedstock (TCFF) [1]. Following our experimental
investigations of nanoparticle synthesis by Tandem-MITP+TCFF method, we have also
developed a numerical model for the synthesis of silicon nanoparticles employing the TandemMITP+TCFF approach [2]. This advanced model enables the simultaneous computation of themodulated electromagnetic thermofluid field, the dynamics of feedstock powder behavior andevaporation, and the nucleation and growth of nanoparticles. It takes into account the intricate
interplay among these processes. In the NP synthesis sequence, nucleation is the initial step,
followed by subsequent condensation and coagulation, leading to the enlargement of NP size.
The present study revolves around elucidating theroles played by condensation and coagulation in thegrowth of nanoparticles within the MITP + TCFF method.
We delve into the efficient conversion of precursor
materials into nanoparticles through meticulously
controlled condensation and coagulation processes.
Fig. 1 indicates an example of the distributions ofcondensation rate (left) and coagulation rate at t=0 ms forconsidering the nanoparticle growth mechanisms intandem-MITP+TCFF method. These are the production
terms of the second moment of the particle size
distribution function [3]. Each indicates the contributionsof heterogeneous condensation and coagulation tonanoparticle growth. As seen, condensation rate becomes
locally higher at edge region at r=35 mm. On the other
hand, coagulation occurs in wider region of 10 mm < r <60 mm in the chamber.
[1] K. Kuraishi, et al., J. Phys. Conf. Ser., 441, 012016(2013).
[2] Y.Tanaka, et al, The 73rd Annual Gaseous Electronics
Conference (GEC2020), GT3.00006, (2020).
[3] R. Furukawa, et al, J. Phys. D: Appl. Phys. 55, 044001(2022).

Fig.1 Condensation rate(left) andcoagulationrate(right)
intandem-modulated
induction
thermal plasmas at a certain
timing.

PSLO-O-3

Surface Blistering and Deuterium Retention in Chemical Vapor Deposition
Tungsten Exposed to Deuterium Plasma
Hao Yin1,2, Long Cheng1,2,*, Yue Yuan1,2 and Guang-Hong Lu1,2
1

2School of Physics, Beihang University,
Beijing 100191, China
LCheng@buaa.edu.cn

Beijing Key Laboratory of Advanced Nuclear Materials and Physics, Beihang University,
Beijing 100191, China

One of the key issues in the realization of commercial fusion nuclear power plants is the
choice of plasma facing materials. Tungsten (W) is currently the main candidate material forthe divertor of the fusion reactor ITER under construction and the first wall of future reactor
DEMO and CFETR, as it is resilient against erosion, has the highest melting point of any metaland shows rather benign behavior under neutron irradiation, as well as low tritium retention.
Chemical vapor deposition (CVD) technology has recently attracted much attention as it is themain way to produce thick tungsten coatings. CVD-W has characteristics of high density, highpurity and high surface coverage with a <001> oriented columnar-grain microstructure. There
have studies reported that CVD-W has good performance on thermal conductivity, thermal
shock and fatigue resistance. This work focuses on the performance of CVD-W under plasma
exposures with a low flux and low fluences to demonstrate the early-stage plasma irradiation
effect in CVD-W including surface morphology changes and deuterium (D) retention.
Four grades of W were used including CVD-W with large-size grains (CVD-L) and smallsize grains (CVD-S), rolled W (ND-W), and recrystallized W (Rec-W) as the reference material.
The average grain size of four samples is ~30.4, 10.9, 10.3, and 55.7 μm, respectively. Aftersurface polishing, samples were irradiated to D plasma in the linear plasma device LEPS withfluences of 5×1024, 1×1025, and 2×1025 m-2. The ion flux was about 1.0×1021 D m-2s-1 andspecimen temperature were set at about 500 K. Thermal desorption spectroscopy was used tomeasure D desorption and total D retention by heating samples up to 1473 K at a constantheating rate of 1 K s-1.
Both types of CVD-W samples featured a columnar grain structure, with the surface normal
direction preferred to close to <001>, especially for CVD-L. They showed good resistance toblistering, with no blisters at low fluence and only several sub-micron-diameter blisters at
higher fluences detected. In ND-W and Rec-W samples, the number and size of blisters
increased with fluence. The D desorption spectra show two desorption peaks in both CVD-W
samples at 520 K and 570-604 K. Whereas in ND-W and Rec-W samples, two peaks were at
520 K and 607-700 K. The total D retention in both types of CVD-W samples was less than
30% of that in ND-W and Rec-W samples. The low D retention in CVD-W samples was
attributed to the low desorption intensities with the peak at 570-604 K.
In this work, CVD-W has shown an outstanding resistance to D-induced blistering and D
retention, which indicates potential advantages as a wall material in terms of surface integrity
and tritium inventory. These results provide an experimental reference for the application of
CVD-W as the wall material in fusion reactor. Further investigations are undergoing on thedepth distribution of D retention and defects to understand the mechanism determining theirradiation effect in CVD-W.

PSLO-O-4

Time-Dependent Density Functional Theory Simulation for Neutralization
Process of Hydrogen Ion Injected onto Graphene
Yuto Toda1, Arimichi Takayama2,1 and Atsushi M. Ito2,1
1

2

Graduate Institute for Advanced Studies, SOKENDAI
322-6 Oroshi-cho, Toki 509-5292, Japan
toda.yuto@nifs.ac.jp

National Institute for Fusion Science, National Institutes of Natural Sciences
322-6 Oroshi-cho, Toki 509-5292, Japan

In previous molecular simulations for plasma-wall interactions (PWI), incident particles
have been approximated as neutral atoms. This was because, due to technical problems, only
potentials between atoms were provided. However, incident particles from the plasma are not
only atoms but also ions and electrons. In contrast, ions on solid surfaces are expected to be
rapidly neutralized. In this study, this process is analyzed in detail using the Time-Dependent
Density Functional Theory (TDDFT)[1].
In the TDDFT, the time evolution of electronic wavefunctions is described by the timedependent Khon-Sham equation:𝜕 𝜓 𝑟⃗, 𝑡1
𝜌 𝑟⃗ , 𝑡
𝑖
Δ
𝑑𝑟⃗
𝑉
𝑉
𝜓 𝑟⃗, 𝑡
|𝑟⃗
𝜕𝑡
2
𝑟⃗|
where 𝑉 is the exchange-correlation term and 𝑉
is external potential. The time
evolution of the nucleus is described by the Ehrenfest molecular dynamics (MD) approach [2].
In this approach, the motion of the nuclei is described by Newton's equation in which the forces
onto atoms are estimated by electronic density distribution in the DFT.
The SALMON code[3] was used for these calculations, and we modified the code to treat
long particle motions. Figure 1 shows a schematic of the normal injection of a hydrogen (H)ion injection onto the graphene. The incident position of the H ion is exactly above the carbon
atom. Before the H ion collides with the carbon atom, the H ion is already neutralized due toelectron transport from the graphene. The partial charge around the hydrogen nucleus was
𝑑𝑟⃗𝜌 𝑟⃗ , where 𝑉 is the Baderestimated as 𝐶
volume arround the H ion. The partial charge 𝐶 becomes
1 before the collision, while it becomes less than 1 after thecollision. This suggests a process of ionization after
neutralization, further analysis under the interpretation of
the probability density in quantum mechanics in order tocompare with experimental observations.
The consideration of electron dynamics allows for moredetailed simulations of plasma-wall interactions, taking into
account ion neutralization and ionization not limited toconventional simulations with neutral atoms.
[1] E. Runge, E.K. Gross, Phys. Rev. Lett. 52 (12) (1984)
997[2] B. F. E. Curchod, U. Rothlisberger, and I. Tavernelli,Chem. Phys. Chem. 14, 1314 (2013).
[3] M. Noda, et al., Comp. Phys. Comm., 235, 356-365,(2019)

Fig. 1: Hydrogen (H) ion
injection onto graphene. (a)Initially, there is no electronic
density around the H ion. (b)The electronic density appears
around the H ion even before
it is close to a typical chemicalbonding distance.

DX-I-8

Simultaneous measurements of F, O and H ground state atom density in anindustry-grade etching plasma
M. K. T. Mo1, S.-N. Hsiao1, M. Sekine1, M. Hori1, and N. Britun1
1

Center for Low-temperature Plasma Sciences, Furo, Chikusa, Nagoya, 464-8603, Japanmo@plasma.engg.nagoya-u.ac.jp

Number density (cm-3)

To continue optimizing semiconductor manufacturing processes, accurate gas chemistry
analysis is required to be correlated to the surface chemistry during the etching stage; thisdepends on knowledge of the species that are present as well as their densities in the plasma.
Optical actinometry is a well-established technique and has been used to detect and measure
the densities of F, O and H [1-3] that play crucial roles in chemical reactions in the etching ofmaterials.
In this work, we report the results of the simultaneous measurements of these atomic
ground state densities in a commercial plasma-etching system via actinometry. Emission frommultiple argon lines were used to minimize the uncertainty of absolute densities to around 20%.
Similarly, electron temperature (Te) values were obtained using a rare gas admixture. Absolutedensities were studied over various conditions and different substrate materials (Si, PI, SiO2).
The measurements were carried out in an industrial etching system where the plasma
was generated between two parallel plates. The conditions studied were: CF4/H2 admixture ratio(8-70% H2), total flow rate (25-200 sccm), and the applied powers at the bottom electrodeconnected to both the low (LF, 0.4 MHz) and high (HF, 40 MHz) frequency power supplies,
from 3.0-7.2 kW and 2.2-5.4 kW, respectively. All were carried out at 3.3 Pa.
Using peak intensity values, the ratios from at least 10 Ar lines were taken withemission from F(703), O(777), O(844), and Hα, Hβ, and Hγ. The results were then averaged todetermine the species densities. For the studied transitions, electron impact excitation crosssections were taken from [4] for Ar and H, [5] for F, and [6] for O.
The F density typically had the highest population, ranging from 1-5×1013 cm-3. Incomparison, O densities were more than an order(a)(b)
of magnitude smaller, and both decreased withhigher H2 proportion. Conversely, H grew withincreasing H2 content from 2×1012 - 5×1013 cm-3,
1E13
overtaking F at ~50% admixture. Increasing the
LF power also promoted all densities linearly,
but at a lesser rate for H2. Changing to SiO2
substrate gave higher O density than Si. Only O
1E12
saw a noticeable decrease as the total flow
increased, while the others remained fairly
F(703)
O(844)
constant.
H(656)
This work is supported by the JSPS
1E11
0 5 10 15 20 25 30 35 2
4
6
8
KAKENHI Tokusui project (grant 19H05462)
H2 (sccm)
LF Power (kW)and Tokyo Electron Miyagi Ltd.
Fig. 1: Number densities as a function of[1] D. R. Boris, et al., Journal of Vacuum Science &(a) H2 flow and (b) LF power. Total flow
Technology A 35, 01A104 (2017).
at 50 sccm, Te = 4 eV, Si substrate.
[2] M. A. Worsley, et al., Journal of Applied Physics 100,083301 (2006).
[3] D. V. Lopaev, et al., Journal of Physics D: Applied Physics 50, 075202 (2017).
[4] Biagi, www.lxcat.net, Last accessed on 26 Jul 2022.
[5] D. R. Boris et al., J. Vac. Sci. Tech. A 35, 01A104 (2017).
[6] R. R. Laher, F. R. Gilmore J. Phys. Chem. Ref. Data, 19, 277 (1990).

DX-O-1

Machine learning prediction of plasma parameters fromoptical emission spectra in argon plasma
Fatima Jenina Arellano1, Minoru Kusaba2, Stephen Wu2,3, Zoltán Donkó1,4, Márton Gyulai4Peter Hartmann4, Tsanko Vaskov Tsankov5, Uwe Czarnetzki5, Ryo Yoshida2,3, and Satoshi
Hamaguchi1
Graduate School of Engineering, Osaka University, Osaka, JapanThe Institute of Statistical Mathematics, Research Organization of Information and Systems, Tachikawa,Japan
3Department of Statistical Science, The Graduate University for Advanced Studies, Tachikawa, Japan
4Wigner Research Centre for Physics, Budapest, Hungary
5Institute for Plasma and Atomic Physics, Ruhr University Bochum, Bochum, Germany
Email: arellano@ppl.eng.osaka-u.ac.jp
1

2

The continuing reduction of micro/nano-electronics device dimensions and the increasing
complexity of their 3D structures necessitate precise control of semiconductor
manufacturing processes with atomic-scale accuracy [1]. Automated process control basedon sensor data can significantly facilitate such high-accuracy manufacturing processes.
Plasma-assisted processes are widely used in semiconductor manufacturing. Opticalemission spectroscopy (OES) for processing plasmas can be a simple and noninvasive
diagnostic tool but deriving the plasma parameters from the OES is not a simple task.
Optical emission spectra can be modelled with a collisional-radiative model (CRM) [2] for
specific gaseous species if the electron density (ne), electron energy distribution function(EEDF), and densities of the ground state gases are provided. In this study, we construct amodel to perform the inverse operation of the CRM for argon (Ar) plasmas, which predicts
the ne and EEDF from OES data at a given Ar gas density (or the Ar gas pressure andtemperature), using machine learning (ML). The ML model was trained with the ne and the
EEDF data obtained from Particle-in-cell/Monte Carlo Collisions (PIC/MCC) simulations[3] and the corresponding OES obtained from the CRM [4]. The ML model used in thisstudy is based on multiple kernel ridge regression and random forest. The simulations were
performed for radiofrequency-driven Ar capacitively-coupled plasmas in the pressure rangeof 2-100 Pa, enclosed in a chamber having an electrode gap of 4 cm. It was found that theML-based inverse CRM predicts the ne and EEDF correctly from given OES data.
[1] K. Arts et al, Plasma Sources Sci. Technol., 31, 103002, (2022).
[2] S. Siepa, S. Danko, T. Tsankov, T. Mussenbrock, and U. Czarnetzki, J. Phys. D: Appl.
Phys., 47, 445201 (2014).
[3] Z. Donko, Plasma Sources Sci. Technol., 20, 024001 (2011).
[4] F. Arellano et al., First-principles simulation of optical emission spectra for low-pressureargon plasmas and its experimental validation, Submitted (2023).

DX-O-2

Numerical Simulation of RF-driven Capacitively Coupled Argon Plasmas
and Comparison with Experimental Observations.
Sarah Alamri1a, Hsing-Che Tsai2, Michiro Isobe1, Fatima Jenina Arellano1,
Charisse Marie D. Cagomoc1, Kazumasa Ikuse1, Tomoko Ito1, Satoshi Sugimoto1, Jong-Shinn Wu2,
Satoshi Hamaguchi1
1

Centre for Atomic Molecular and Technology, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japanasarah.alamri@ppl.eng.osaka-u.ac.jp
2 Department of Mechanical Engineering, National Yang Ming Chiao Tung University, 1001 University Road,
Hsinchu, Taiwan

This work aims to understand radio-frequency (RF) argon (Ar) capacitively coupledplasmas (CCPs) by comparing experimental measurements of the plasmas with the results ofnumerical simulation based on a two-dimensional (2D) self-consistent fluid-based plasma
model coupled with an external circuit model. In this plasma model, the electron dynamics isgoverned by the electron continuity, momentum, and energy density equation where themomentum equation is simplified as the drift-diffusion approximation and combined with theelectron continuity. The transport coefficients and reaction rate constants, including theionization rates, are evaluated from BOLSIG+. The ion dynamics is governed by the full massand momentum conservation equations, including the ion convection. The system is assumed
to be electrostatic and the plasma equations coupled with Poisson’s equation are solved on
unstructured grids via the finite-volume method with a parallel computing platform Ultrafast
Parallel Processing (ultraMPP). [1]Following the existing experimental plasmas system, 2D-axisymmetric Ar CCPs between
unequal-sized electrodes were simulated in this study. The neutral Ar gas was assumed to beuniformly distributed and constant in time with a gas temperature of 300 K. The electrode gap
distance was 30 mm, the diameter of the grounded electrode was 80 mm, and the diameter ofthe powered electrode was 190 mm. The chamber wall was also grounded. The applied voltage
had a sinusoidal form with a frequency of 13.56 MHz. The voltage applied to the electrode wasmeasured close to the electrode but outside the chamber wall, so the measured voltage wasslightly different from the actual voltage applied to the electrodes. Therefore, an external circuit
model was used to estimate the exact voltage applied to the powered electrode. In the simulation,
the pressure, the peak-to-peak voltage Vpp (i.e., half of which is the applied voltage amplitude),and the direct current (DC) bias voltage VDC were specified as input parameters. The impedancevalues of circuit elements of the external circuit model were determined experimentally with a
network analyzer. It has been found that, with the experimentally measured Vpp and VDC, thenumerically simulated current at the location of the current measurement probe, including thestray current, is found to be in reasonable agreement with the experimentally measured current.
The simulation also shows that a large volume of plasma is generated in space below thepowered electrode, in addition to the main plasma generated between the upper and electrode.
References[1] K. -L. Chen et al., IEEE Trans. Plasma Sci. 49 (1) pp. 104-119 (2021).

DX-O-3

Preliminary Investigation of Methane Plasmalysis in an AtmosphericPressure Gliding Arc Plasma
Pierre MATHIEU1, Abhyuday CHATTERJEE1, Nepal CHANDRA ROY1, Rony
SNYDERS1,2
1

Chimie des Interactions Plasma-Surfaces, University of Mons, Mons, Belgium
2
Materia Nova Research Center, Mons, Belgium

One of today’s most important challenges is the reduction of our greenhouse gas
emissions below the maximum storage capacity of our Planet’s natural carbon wells. In thisline, we must insure our energy mixes’ decarbonation through the implementation of clean
technologies to harvest solar, wind, hydraulic and geothermal energies.
But if we want to activate the switch from fossil fuels toward clean electricity, we will
have to adopt efficient electricity storage technologies as well, and hydrogen is foreseen to be
one of them. However, the current main production method of this fuel remains problematic, as
it is estimated to emit about 12 kg of CO2 for only 1 kg of H2 synthetized.[1] This industrial
process consists in reforming methane in water vapour: CH4 + H2O → CO + 3 H2, followed by
the water-gas shift reaction: CO + H2O → CO2 + H2, and is known as steam methane reforming(SMR). It produces large amounts of CO2 and costs about 285 kJ of energy per mole of H2.
There is another approach to achieve methane reforming to produce H2, with no CO2emissions, and that has an energy cost of only 74.58 kJ per mole of H2. This approach is thepyrolysis of methane in an electric discharge, using non-oxidative conditions: CH4 → C(s) + 2
H2. It was also shown with this process that one can tune its selectivity toward several othervalue-added products, such as acetylene and ethylene, by implementing the proper experimental
parameters (plasma power, gas flow, gas mix composition, catalysts).[2]This work presents the results of a preliminary study of plasma-assisted methane
reforming, conducted in an atmospheric pressure gliding arc discharge, using CH4/Ar mixtures.
The CH4/Ar ratio varied from 0.2 to 0.4 to insure the stability of the discharge and as a resultof optical signals quality optimisation. Optical Emission Spectroscopy was used to evaluate theimpact of the plasma power, the total injected gas flow and the CH4/Ar ratio on the rotationaland vibrational temperatures (Trot and Tvib) of the C2 species and on the electronic density (ne).
The observed correlation between ne and Trot suggests that, in our experimental window, theaverage amount of energy brought to heavy particles by an electronic impact allows rotational
excitations (implying more gas heating), but does not promote vibrational excitations(activating a more energy-efficient chemistry).
Finally, the CH4 conversion rate and H2 selectivity of the process were determinedthrough gas chromatography. Maximum values of 30% and 57.6% were achieved for theseparameters, respectively. The lowest energy cost obtained was therefore about 150 kJ/LCH4.
[1] M. Gautier et al., International Journal of Hydrogen Energy, 42(47), 28140–28156 (2017)[2] M. Scapinello et al., Chemical Engineering & Processing: Process Intensification, 117,
120–140 (2017)

GN-KN-1

Broadening plasma polymerization process for functional coatings
Ju-Liang He1,2, Xuan-Xuan Chang1, Yu-Han Wei1, Ping-Yen Hsieh1,2, Ying-Hung Chen1,2
and Meng-Heng Lai3
Department of Materials Science and Engineering, Feng Chia University
No. 100, Wenhwa Road, Seatwen District, Taichung City 407102, Taiwan.

1

jlhe@o365.fcu.edu.tw

Institute of Plasma, Feng Chia University
No. 100, Wenhwa Road, Seatwen District, Taichung City 407102, Taiwan.
2

3 Qual-Inno Technology Corporation
16F.-7, No. 241, Sec. 3, Wenxin Road, Seatwen District, Taichung City 407330, Taiwan.

With the growing need for broadening the applications of surface modification, theevolution of plasma power generators has led to the progress of plasma coating techniques,particularly generating a very short and stable impulse waveform to improve film quality orarchitect coating structure. Considering the Yasuda factor to predict the structure of obtained
plasma polymerized films, the power output waveform is a key factor that affects the structure
and thus the performance of the plasma polymerized films. With implementation of an impulse
power supply, featuring a very short pulse (in a few microseconds), low duty cycle, and low
plasma power, using impulse plasma polymerization (iP3) to grow plasma parylene coating(iP4C) on silicone rubber is proposed in this study. The iP4C is able to provide low friction,
anti-sticking, and biocompatibility properties on silicone catheters for reducing the pain andforeign sensation during invasion. To further meet the demand for antibacterial function, hollow
cathode discharge (HCD) in combination with iP3 to synthesize silver containing plasma
parylene coating (Ag-iP4C) was also developed, where the silver HCD tube serves as the silver
incorporating source in situ. Hence, this report will adequately investigate the mechanism ofmolecular structure modulation for iP4C by adjusting pulse time; in addition, the control ofsilver containing level and the characteristics of Ag-iP4C will also be discussed in detail.
Finally, such iP4C technique is currently transferred to realize the commercial activity as wellas providing total solution service of plasma polymeried functional surface modification.

GN-I-8

Development of Atmospheric Pressure Plasma Sources for Material
Modification
Magdaleno R. Vasquez Jr., Mark D. Ilasin, Marlo Nicole R. Gilos, Bryndell J. Alcantara,
Eunice G. Ramirez, Gericca M. Dol, Mary Mark Jeffry D. De Leon, Kathrina Lois M. Taaca
Department of Mining, Metallurgical, and Materials Engineering, College of Engineering, University of thePhilippines Diliman, Quezon City 1101 Philippines
mrvasquez2@up.edu.ph

Atmospheric pressure plasma systems have been gaining considerable attention due to theirpotential uses in various fields and industries. These systems are simple, inexpensive, easy touse, low-maintenance, fast, and generally safe, making them an attractive option. These systems
are used to treat or modify surfaces because of their ability to produce metastable active species.
The vacuum-less operation allows for the processing of different materials, including liquids.
In addition, large-area treatment is also realized by taking advantage of the flexibility of
atmospheric pressure plasma systems. In this report, different custom-built plasma system
configurations (Fig. 1), such as arc discharge plasma and dielectric barrier discharge (DBD),
were developed and used to modify material surfaces using different gases. A cold atmosphericpressure plasma jet was used to condition polymeric surfaces such as high-density polyethylene(HDPE) to improve the adhesion of water-based paints [1]. Another configuration was used totreat chitosan-arcylic acid hydrogels [2]. Pretreatment of low-density polyethylene (LDPE)
sheets using plasma accelerated LDPE biodegradation. A DBD system was used to treat riceseeds and the effect on germination was evaluated. A plasma jet made of 3D printed
components was able to generate an argon:air plasma jet. This was used to modify bamboo
surfaces to improve the adhesion of polyvinyl acetate. The same system was used to clean anddisinfect metallic surfaces used in food processing. Continuous development and advancementof versatile atmospheric pressure plasma systems will improve surface processing technologies
and reduce operating costs.

Fig. 1: Images of custom-built atmospheric pressure plasma systems for material modification.

[1] M. J. D. De Leon and M. R. Vasquez, Mater. Res. Exp. 8,105306 (2021).
[2] K. L. M. Taaca, M. J. D. De Leon, K. Thumanu, H. Nakajima, N. Chanlek, E. I. Prieto,and M. R. Vasquez, Colloids Surf. A: Physicochem. Eng. 637, 128233 (2022).

GN-I-9

Surface Modification by Non-Thermal Plasma for Gaseous Mercury
RemovalJinjing Luo, Lurong Ye, Mingchang Jin
College of the Environment & Ecology
Xiamen University, China
luojj27@xmu.edu.cn

Dielectric barrier discharge plasma pre-treatment was conducted to introduce typicalfunctional groups on the surface of carbonaceous materials. Plasma generated from fivedifferent discharge gases were investigated their effects on surface modification. Ocean optics
spectrometers (OES) and fourier transform infrared spectrometer (FTIR) were used to analyze
the generated plasma and gases. X-ray photoelectron spectroscopy (XPS), FTIR, scanningelectron microscope (SEM) and X-ray absorption fine structure (XAFS) were used to analyze
physical and chemical properties of absorbents. ·OH and ·O were believed to generated bydischarge gases and reacted with carbonaceous materials and introduce oxygen-containing
functional groups on the surface. Mercury absorption mechanism was also discussed in thisstudy and the schematic diagram of the surface modification mechanism was shown in Figure
1.

Figure 1 Schematic diagram of the principle of Hg0 adsorption by DBD modified
carbonaceous material[1] Estupiñán E G, Stickel R E,Wine P H J C P L. An investigation of N 2O production fromquenching of OH( A 2Σ +) by N2. 2001,336(1):109-117.
[2] Sun R, Zhu H, Shi M, et al. Preparation of fly ash adsorbents utilizing non-thermal plasma
to add S active sites for Hg0 removal from flue gas. Fuel, 2020,266(11):6936-6942.
[3] Frentiu T, Ponta M, Mihaltan A I, et al. Quenching of the OH and nitrogen molecularemission by methane addition in an Ar capacitively coupled plasma to remove spectralinterference in lead determination by atomic fluorescence spectrometry. 2010,65(7):565-570.

GN-O-1

Amorphous Carbon Film Deposition using Low-energy Ions
Mark D. Ilasin, Lance Tristan Oliver R. Pengson, and Magdaleno R. Vasquez Jr.
Department of Mining, Metallurgical, and Materials Engineering, College of Engineering,
University of the Philippines Diliman, Quezon City, Philippines
mdilasin@up.edu.phAmorphous carbon (C) films have been of particular interest in recent years because of its
applications in tribology and in electronics [1] due to its chemical inertness, high hardness, andoptical transparency in visible light and infrared [2,3]. In this study, low-energy ion beams wereextracted to deposit amorphous C films. A custom-built hot cathode ion source [4] with acylindrical multi-cusp configuration was used to extract ions with energies around 100 eV.
Figure 1 shows the uniformity the extracted ion beam from the 4-cm diameter extractor atdifferent extraction potential. An admixture of acetylene (C2H2, 99.95%) and argon (Ar,99.999%) with predefined pressure ratio were ionized and eventually extracted in a highly
transparent two-electrode ion extractor. Silicon (Si) substrates were positioned downstream
opposite the extractors where thin C films were deposited. The deposited material wascharacterized using Raman spectroscopy, atomic force microscopy (AFM), andnanoindentation. Raman spectral analysis revealed the presence of up to 70% sp3 C. AFM
characterizations of the thin films showed very smooth surfaces with a maximum root-meansquare roughness of 0.57 nm. Nanoindentation modulus and hardness revealed a mean value ofapproximately 216 and 10 GPa, respectively.

Fig. 1. Current density profile of ion beams at different extraction potential.
[1] J Robertson, Surface and Coatings Technology 50 (1992)[2] J Robertson, Mater. Sci. Eng. R 37 (2002) 129-281[3] A Hamdan, et al., Thin Solid Films 599 (2016) 84-97[4] M Vasquez, et al., Vacuum 187 (2022) 110067

GN-O-2

Selective removal of graphene by irradiation of remote oxygen plasma
Liugang Hu1, Kenji Ishikawa2, Takayoshi Tsutsumi2, Thi-Thuy-Nga Nguyen2, Shih-Nan
Hsiao2, Hiroki Kondo2, Makoto Sekine2, and Masaru Hori2
1

Graduate School of Engineering, Nagoya University
Furo, Chikusa, Nagoya 464-8603, Japan
hu.liugang.k5@s.mail.nagoya-u.ac.jp
2

Center for Low-temperature Plasma Sciences
Furo, Chikusa, Nagoya 464-8603, Japan

1. Introduction
Control of layers of stacked graphene is plausible for realizing next-generation single-layerelectronic devices. We reported in-situ electron microscopic observation of continuous etch ofmultilayer stacked graphene using an exposure of oxygen radicals [1]. Defects on plane of
single layer of graphene (SLG) were formed during oxygen radical irradiation [2]. To realize
atomic layer etching (ALE) technology, Selective removal of SLG between bilayer graphene(BLG) was discovered and the etch mechanism has been investigated by Raman spectroscopy,
atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS).
2. Experimental
The oxygen plasma was generated using the microwave (2.45 GHz) cavity in flowing O2 gas
with a flow rate of 2.5 sccm and at a pressure of approximately 5 Pa. The microwave power
was 50 W to generate plasma in remote plasma system, distanced 29 cm from discharge to thesample position. The irradiation time was 60 and 120 minutes. CVD-grown (Chemical vapor
deposition) graphene (EM Japan, G-45R-4) was used. In this preparation, an as-grown graphenesheet was transferred to a coated polymer and then onto a SiO2 film on Si substrate [3].
3. Results and Discussion
Figure 1 (a) shows an optical image of the initial sample. Inset shows overlay of a mappingof Raman signals for BLG and SLG. The BLG area is labeled A, and the SLG area is labelled
B. AFM images at the identical position are shown in Figure 1, taken before irradiation (b) andafter 120-min-irradiation (c). Raman spectra atdifferent positions A and B are different in increaseof D peak at 1350 cm-1 and 2D peak at 2700 cm-1.
The 2D peak intensity almost disappeared at the SLG
position. On the other hand, at BLG position, the Dpeak increased but unchanged 2D peak. Selectively,
SLG was removed by etching, while BLG remainedon the surface after the 120-min-irradiation. A
control of layers of stacked graphene can be realized.
Meanwhile, the etching of SLG/BLG occurred at theplane dominantly but considering the dangling bonds
should exist at the edge of graphene, we supposed Fig. 1 (a) A optical microscopic image
that some bonding formed (C-OH) during CVD- of graphene overlays a mapping of thegrown or because of the nature of graphene.
Raman signals from BLG (labelled 'A')
References
and SLG (labelled 'B'). (b, c) AFM[1] H. Sugiura et al., Carbon 170, 93-99 (2020).
images and (d, e) Raman spectra at the[2] C-H. Huang et al., Carbon 73, 244 (2014).
A and B positions of the initial and the[3] X. Liang et al., ACS Nano 5, 9144 (2011).
remote plasma-treated graphene.

GN-O-3Synthesis and characteristics of carbon nanowalls using two-step growth
combining different plasma chemical vapor deposition methods
Ngo Quang Minh1, Ngo Van Nong2, Osamu Oda2, Masaru Hori2 and Kenji Ishikawa2
1

Graduate School of Engineering, Nagoya University, Nagoya, 464-8601, Japan
2
Center for Low-Temperature Plasma Sciences, Nagoya University, Japan
Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8601, Japane-mail: ngo.minh.quang.j6@s.mail.nagoya-u.ac.jp

1. Introduction
Carbon nanowalls (CNWs) are self-supported nanostructures of graphene sheets grownalmost vertically on substrates. To date, CNWs can be synthesized by various plasma methods
such as microwave plasma enhanced chemical vapor deposition (MPCVD), inductively coupledplasma chemical vapor deposition (ICP-CVD), and capacitively coupled plasma chemical
vapor deposition (CCP-CVD) [1]. The morphology and density of CNWs have a strong
influence on their unique properties.. However, using a single plasma method, it is difficult toeither control the morphology or improve the density of CNWs. One solutions is to apply
plasma treatment (e.g., oxygen plasma treatment), but this has a high etching effect and thus
reduces the thickness of CNWs.
In this study, CNWs were grown using an innovative two-step plasma method thatcombined radical injection plasma enhanced chemical vapor deposition (RI-PECVD) and CCPCVD.
2. Experimental
CNWs were grown in two steps: step 1 (RI-PECVD) and step 2 (CCP-CVD). The
temperature (700 oC), growth period (10 mins), and gas flow rates (CH4/H2) were the same
parameters for both two steps. While the pressure in step 1 was kept at 1 Pa, it was 10 Pa in thesecond step. The morphology of CNWs was observed by scanning electron microscopy (SEM
– SU-8230 model, Hitachi High-Technologies), and Raman spectra were used to investigate
CNWs‘ structural properties (Renishaw inVia system). The static water contact angle wasmeasured by a sessile drop method to investigate CNWs‘ surface wettability.
3. Results and discussion
Figure 1 shows the wall density of CNWs synthesized by single plasma methods of either
RI-PECVD or CCP-CVD in comparison with the CNWs grown by the two-step plasma
methods combining RI-PECVD and CCP-CVD. As canbe seen, the wall density of branched CNWs grown by thetwo-step combined plasma method exhibited the highest
density of 74 wall units/μm2, which is more than 5 times
larger than the CNWs synthesized by the RI-PECVD
single-step methods.
4. Conclusion
Combining two different plasma methods of RIPECVD and CCP-CVD in a proper order could create CNWs
with highly dense and multi-branched morphology.
References[1] M. Hiramatsu and M. Hori, ISBN 978-3-211-99718-5

Fig. 1: Wall density of the
CNWs grown by: RIPECVD, CCP-CVD and thetwo-step plasma methods
combining RI-PECVD and
CCP-CVD.

October 18（Wednesday）

PL-5

Beryllium Dust Preparation to Mimic Particle Formation in Fusion Devices
Cristian P. Lungu, Corneliu Porosnicu, Paul Dinca, Oana Pompilian, Bogdan Butoi, Cornel
StaicuNational Institue for Laser, Plasma and Radiation Physics Atomistior 409, Magurele, Ilfov, 077125 Romania
cristian.lungu@inflpr.ro

The safety and performance of the fusion machine operation [1] could be affected by
the sputtering or vaporization of some “particulates that might have been produced byblistering or abrasion of wall in previous discharges” [2]. The dust formation in the fusion
machine in case of accidental leaks could be influenced by air and water, as possible coolant
candidates to be used in ITER. The dust formation and release mechanisms have a direct
impact on dust dynamics by dictating both the initial conditions and the regimes of plasma
particle collection by the dust. In particular, dust and droplets in metal machines are relatively
large sizes, implying inhibition of electron collection due to the presence of strong magnetic
fields and, leading to significant release speeds, an inertia-dominated motion.
We studied the influence of air and water leaks over the dust production of beryllium
in order to improve the prediction of Be dust generation. Using a ball milling as well as anarching procedure, beryllium dust was obtained starting from a beryllium pebble/2 inch target
in air and water environment. The dust shape and size obtained in our experiments weresimilar with the ones collected from the JET machine.
The crystalline phase composition analysis shows peaks of Be, BeO, Al2O3 and
SiO2. The observed shifts to small angles suggest the modification of the interplanar spacingof the Be crystalline lattice, due the presence of an uniform stress state responsible for thelattice strain. The BeO diffraction peaks are observed for wet conditions prepared samples.
Alumina (Al2O3) and agate (SiO2) used in the milling process appeared too: more obvious
under wet conditions.
Different dust powders prepared in wet and dry conditions were studied using the
Thermal Desorption Spectroscopy (TDS). Formation of oxides and nitrides: BeO, H2O, N2,
Be(OH)2 were found in higher content for wet environment prepared samples. Be, O2 andBe3N2 content was higher for samples prepared in dry condition, suggesting that the water ispresent in Be dust as: non-reacted pure H2O, oxygen that forms BeO and as hydroxide to form
Be(OH)2. The maximum desorption temperatures were 190oC for H2O and 540oC for BeO.
The results presented in this work prove the capability to obtain Be dust samples thatmimic the real dust collected from JET after the ILW campaigns. Since the collected real dust
is limited in quantities, their properties and varying result in measurement values willcontribute in prediction of their behavior in extreme conditions of plasma operation in fusion
devices.
The talk will also focus on investigating the impact of fusion plasma on the first walltiles, as well as exploring the production techniques using High-power impulse magnetron
sputtering (HiPIMS) and characterizing Be reference coatings with different composition,
morphology, and grain structure. The findings from the research presented offers valuable
insights into the dust formation and deposition phenomena occurring in large-scale beryllium
structures.
[1] M. Shimada, R.A. Pitts, S. Ciattaglia, et al., J. Nucl. Mater, 438 (2013),p.S996.
[2] S. Ratynskaia, A. Bortolon, et al, Rev of Modern Plasma Physics (2022) 6:20.

PL-6

Plasma Treatment of Water for Agricultural Production
Juergen F. Kolb¸ Marcel Schneider, Henrike Brust, Raphael Rataj, Nicola Wannicke,
Volker Brüser and Klaus-Dieter Weltmann
Leibniz Institute for Plasma Science and Technology (INP)
Felix-Hausdorff-Strasse 2, 17489 Greifswald, Germany
juergen.kolb@inp-greifswald.de

Water is a crucial resource for the cultivation and processing of crops. However, asustainable supply is challenged by increasing scarcity, e.g. due to climate change, andpollutants, e.g. agrochemicals. Accordingly, mitigation and management practices need to be
developed to address the problems. Plasma treatments can offer technical solutions, which, on
the one hand, can be used for water cleaning, and, on the other hand, provide environmentallybenign means to replace pesticides and fertilizers. In addition, they can also be applied to
improve current processes in crop farming, food production, and biomass valorization. The
different possible applications of plasma methods along the entire food value chain “from farm
to fork” require dedicated and special approaches, which take into account respective processes,
in particular with respect to treatment volumes. Therefore, the INP develops plasma methods
for different applications in crop cultivation and processing in several projects and in particular
the comprehensive activity “Physics for Food” [1].
The basis of all these efforts is a thorough understanding of the mechanisms of action for
the treatment of aqueous solutions with plasma. Primarily interesting are the chemical species
that are generated. Hence, we have carefully investigated the correlation of discharge
mechanisms, especially for discharges in water, with reaction rates of hydrogen peroxide inparticular, which can serve as a quantitative measure to compare different plasma treatment
concepts [2]. However, not all of the approaches, that are promising in the laboratory, can bereasonably transferred towards the treatment of larger volumes [3]. For the processdevelopment for water cleaning and reuse, we have, therefore, deployed a pilot water treatment
system, which combines established methods with a plasma or ultrasound treatment forthroughputs of up to 2000 ltr/h. In addition to the efficacy, an important result was the proof of
economic competitiveness of the plasma treatments. A similar approach was also successful forthe improved degradation of residual biomass to increase biogas production by combining a
microwave plasma together with an ultrasound exposure, which were both operated infermentation residues with up to 1 kW for each. The objective of a more recent effort is the
fixation of nitrogen as an alternative to synthetic fertilizers, especially concerning the HaberBosch process. However, the benefits of the application of plasma-treated water are not limited
to fertilization. Other reactive oxygen and nitrogen species, introduced into the water, have thepotential to stimulate plant metabolic processes and even induce a memory or tolerance,
respectively, regarding drought stress [4]. These processes can and should conceivably also be
expanded towards preserving and restoring soil health.
The presentation will discuss, based on basic mechanisms, the need for the different
outlined applications and report on our experience of specific approaches for relevant volumes,
environments, and possible solutions to emerging challenges in agricultural production.
[1] https://physicsforfood.org/english-summary[2] R. Rataj, M. Werneburg, H. Below, J.F. Kolb, ChemPhysChem, e202300143 (2023).
[3] M. Schneider, R. Rataj, L. Blàha, J.F. Kolb, Chem. Eng. J., 451, 138984 (2023).
[4] F. Bussmann, A. Krüger, C. Scholz et al., J. Plant Growth Regulation, 42, 3274 (2023).

PSLO-I-3

Mechanism of blistering and retention in recrystallized tungsten exposed todeuterium plasma in the linear plasma device STEPLong Cheng*, Yi-Wen Sun, Hao Yin, Yue Yuan and Guang-Hong Lu
School of Physics, Beihang University,
Beijing 100191, China
LCheng@buaa.edu.cn

Blistering in tungsten (W) is an typical observation of fusion plasma and materialinteraction during low-energy and high-flux hydrogen (H) plasma exposure, which could
degrade material’s integrity and tritium fuel retention. It is therefore important to understandblistering mechanisms and find a way mitigating blistering. In this work, blistering anddeuterium (D) retention in W were investigated using the linear plasma device STEP at Beihang
University. Defect and microstructure in the vicinity of blisters were investigated using electron
microscopes. D retention was studied using thermal desorption spectroscopy (TDS) andmodeled using the rate theory code. Mechanism of blistering based on the dislocation nucleation
is proposed and D retention was understood with the presence of blister-induced defects.
A linear plasma device STEP was constructed at Beihang University, which could deliver
a flux up to 1×1023 ions m-2s-1. A series of D plasma exposures was performed using
recrystallized W samples exposed at 500 K with fluences up to 1.0×1028 ions m-2 at a flux of~1022 ions m-2s-1 and a surface temperature of ~500-500 K. Transmission electron microscope(TEM) observations demonstrated dislocations and dislocation tangles in the vicinity of intragranular blisters. In TEM, 〈001〉 edge dislocations were identified and supposed to form via〈111〉 edge dislocations interaction. Considering the high tendency to crack for a 〈001〉 edge
dislocation, its formation is proposed as the nucleation of a blister. An increase in both blisterdensity and D retention was observed with increasing fluence. Based on the simulation of TDS
using the rate theory code, defects were found to be located at a depth of tens of microns, whichcoincided with the average grain size. The majority of defects was supposed to be dislocations
as identified in TEM. It is suggested that these defects can diffuse deep into the material but
were hindered by grain boundaried at a certain depth, which resulted in the evolution of bothpeak desorption intentisty and temperature with the increasing fluence. Regarding thecontribution of blister-induced defects on retention, a blister-dominated retention mechanism
is proposed to describe retention in conditions when blistering is severe.
To summarize, blistering and D retention in recrystallized W were systematicallyinvestigated using the linear plasma device STEP at Beihang University. A 〈001〉 edge
dislocation nucleating mechanism and a blister-dominated retention mechanism are proposed
to understand experimental findings. This work helps improving the understanding of theplasma-induced defect production and hydrogen isotopes retention in W in the context of fusionedge plasma and wall interaction, and indicates the potential contribution of plasma-induced
defects to the tritium inventory in the stage of steady-state operation in fusion devices.

PSLO-I-4

Spectroscopic measurement of deuterium recycling at molybdenum
surfaces
Dogyun Hwangbo1 and Daisuke Nishijima2
1

2

Faculty of Pure and Applied Sciences, University of Tsukuba,
1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577, Japanhwangbo@prc.tsukuba.ac.jp

Center for Energy Research, University of California San Diego,
9500 Gilman Dr., La Jolla, CA 92093-0417, USA

In a fusion device, hydrogen isotope recycling [1] plays an important role in determining
the edge plasma condition and ELM (edge localized mode) behavior [2], as well as volume
recombination processes in the divertor [3]. Note that hydrogen isotope recycling occurs inseveral mechanisms [1], including reflection, sputtering, desorption, etc. Depending on themechanism, the released form is either atom or molecule, which has some translational andinternal (electronic and rovibrational) energy distributions. Thus, spectroscopic measurements
have been used to investigate hydrogen isotope recycling.
In this study, we aim to better understand how hydrogen isotope recycling is affected by thefollowing factors: sample temperature, Ts, neutral gas pressure, PD2, incident ion energy, Ei, andsurface morphology. Experiment was performed in the linear plasma device PISCES-A.
Deuterium (D) plasma light emission was measured near a molybdenum (Mo) target using an
Echelle-type spectrometer and a hyperspectral imaging (HSI) camera (SpecimIQ). The line-ofsight of both systems was set to be parallel to thetarget surface. To explore the effect of surface
nanostructures, fuzz, on D recycling, a ~1 m thick
Mo fuzz layer was formed due to He plasma
exposure prior to D plasma measurements.
Preliminary HSI analyses show that theemission from both D atomic Balmer series and theFulcher band (580-640 nm) of D2 molecules is notclearly affected by the presence of fuzz on thesurface. Instead, the emission appears to depend on
the other factors, PD2 and Ei. Fig. 1(a) presents an
example of 2 dimensional image of D line
intensity extracted from HSI spectra, which isnormalized at ~84 mm. Using the HSI spectra, The
intensity ratio of D/D is surveyed with varying
Fig. 1: (a) An example image of 2PD2 and Ei. Fig. 1(b) shows different trends ofD/D along the distance from the surface. At dimensional D line intensity. (b)higher PD2, the ratio has a sudden decrease near the D/D ratio distibution against the
distance from the surface.
surface, whereas it gradually decreases from ~80mm at lower PD2 and increases within several mm from the surface due probably to reflected D
atoms at the excited states. For further understanding, effects of Ts, PD2, and Ei on the internalenergy states of recycled D atoms and D2 molecules will be analyzed in detail.
[1] Ph. Mertens et al., Plasma Phys. Control. Fusion 43, A349 (2001).
[2] S. Brezinsek et al., Phys. Scr. T167, 014076 (2016).
[3] K. Sawada et al., Contrib. Plasma Phys. 60, 153 (2020).

PSLO-I-5

Study on effects of neutral particle behavior on detached plasma
formation using linear plasma device and modeling
Yuki Hayashi1,2, Noriyasu Ohno3, Hirohiko Tanaka3, Hiroki Natsume4, Kento Sugiura3,
Ryoji Mano3, Shota Masuda5, Ryusei Migita5, Keiji Sawada5, Shin Kajita6,
Tadashi Thujihara3, Hiroshi Ohshima3, Mitsutoshi Aramaki7 and Gakushi Kawamura1,2
National Institute for Fusion Science, Toki 509-5292, Japan
2 SOKENDAI, Toki 509-5292, Japan
3 Nagoya University, Nagoya 464-8603, Japan
4 National Institutes for Quantum Science and Technology, Naka 311-0193, Japan
5 Shinshu University, Nagano 380-8553, Japan
6 The University of Tokyo, Kashiwa 277-8561, Japan
7 Nihon University, Chiba 275-8575, Japanhayashi.yuki@nifs.ac.jp
1

Neutral particle plays an important role in determining the edge plasma property
especially under high neutral pressure condition associated with plasma detachment. In
detached plasma regime with low temperature, neutral temperature, Tn, is an importantparameter acting as the lower limit of Te. The purpose of the present study is to elucidate theinfluence of Tn on detached plasma formation by experiments using the linear plasma device
NAGDIS-II and the modeling which couples plasma fluid code with the neutral transport code.
A DC arc discharge produced helium plasma in a steady-state in NAGDIS-II. The plasma
was terminated with a target plate. When the additional helium gas was injected from the second
gas puffing port behind the target plate, the neutral pressure, Pn, increased and the detachedrecombining plasma was obtained due to the enhanced plasma-neutral interactions.
Figure 1 shows the Pn dependence of total ion current into the negatively-biased target plate,
Itarget. The measurements were conducted under high and low Tn conditions achieved bychanging the neutral gas puffing and pumping rates. When the puffing and pumping rates
increase, Tn should decrease. Fig 1 shows Itarget decreased by increasing the puffing and pumping
rates. The result indicated the enhancement of volume recombination processes by increasing
the puffing and pumping rates even in the similar Pn. It could be concluded that the detachedplasma formation was affected by Tn which was controlled by the puffing and pumping.

[1] M. Aramaki, et al., AIP Advances 8 (2018) 015308.

400

Itarget [mA]

On the other hand, Tn of meta-stable atoms ismeasured by using a laser absorption profile with
Doppler broadening at the transition of 23S-23P [1]. In thecase of high puffing and pumping rates, Tn (23S) was
higher than that in low puffing and pumping rates. The
enhanced recombination in the high puffing and pumping
rates might increase the number of meta-stable atoms
with 23S state which reflects the ion temperature.

● High puﬃng&●
pumping
Low Tratesn◆ Low puﬃng◆ High Tn& pumping rates

300
200
100
0

18

19

20

21

PPend
[mTorr]n [mTorr]

22

23

Fig. 1 Pn dependences of Itarget withhigh and low puffing and pumping
rates.

PSLO-I-6

Newly developed integrated transport code for detached plasma simulation
Hirohiko Tanaka1, Hiroki Natsume2,3, Shota Masuda4, Kento Sugiura3, Hideya Umezawa4,
Ryoji Mano3, Yuki Hayashi5, Kazuo Hoshino6, Keiji Sawada4, Noriyasu Ohno3
1

2

3

Institute of Materials and Systems for Sustainability, Nagoya University,
Furo, Chikusa, Nagoya 464-8603, Japanh-tanaka@ees.nagoya-u.ac.jp

National Institutes for Quantum Science and Technology, Naka Fusion Insutitute,801-1 Mukoyama, Naka, Ibaraki 311-0193, Japan

Graduate School of Engineering, Nagoya University, Furo, Chikusa, Nagoya 464-8603, Japan
4

5

Institute of Engineering, Shinshu University, Nagano 380-8553, Japan

National Institute for Fusion Science, National Institutes of Natural Sciences, Toki 509-5292, Japan
6

Faculty of Science and Technology, Keio University, Yokohama 223-8522, Japan

Sufficient divertor heat load reduction is an important issue for future fusion reactors. In the
research fields of scrape-off layer (SOL) and plasma-wall interaction (PWI), the establishmentof reliable simulation code for the detached plasma, which is expected to be one of thepromising solutions to reduce divertor heat flux, has become a hot topic that will determine thesuccess of the reactor. Although many simulation codes have been developed, quantitative
reproduction of experimantally observed detached plasmas has not yet been achieved.
In this study, a new integrated transport code named DISCOVER (Detached plasma
Integrated Simulation Code with Various Elastic/inelastic Reactions) [1] has been developed to
examine the effects of atomic and molecular processes on the formation of detached plasmas
in a linear magnetic field geometry. This code consists of a plasma fluid code [2], a kinetic
neutral transport code, and a collisional radiative code. The linear plasma device NAGDIS-II
is used as the simulation target.
As a first step, attached and detached helium plasmas were calculated in which the transportof metastable atoms was solved. Compared to the case where metastable-atom transport isignored, ionization is enhanced upstream in the case where the transport is taken into account,and the density rollover position shifts upstream. In the presentation, the formation process ofdetached plasma in the linear device and future plans will also be explained.
[1] H. Natsume et al., submitted to Nucl. Fusion.
[2] H. Tanaka et al., Phys. Plasmas 27, 102505 (2020).

PSLO-I-7

Development of a Plasma Fluid Model Covering a Range of Coulomb
Collisionality by Comparison with a Particle-in-cell Model
Satoshi Togo1, Kenzo Ibano2, Tomonori Takizuka2, Yuki Homma3, Keishi Homma1,
Kazuma Emoto1, Naomichi Ezumi1 and Mizuki Sakamoto1
1

Plasma Research Center, University of Tsukuba,
1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577, Japan
togo@prc.tsukuba.ac.jp
2

Graduate School of Engineering, Osaka University,
1-1 Yamadaoka, Suita, Osaka 305-8577, Japan

3

National Institutes for Quantum Science and Technology,
2-166 Obuchi-Omotedate, Rokkasho, Aomori 039-3212, Japan

Plasma fluid models are useful tools to compute profiles of macroscopic quantities ofplasmas such as the density, flow, and pressure, with comparatively low computational cost,
and thus have been used in various plasma applications. In simulations for the divertor designof plasma fusion reactors, the Braginskii model [1] is widely used to model the fuel plasmas.
However, it was pointed out in a DEMO reactor that the kinetic-effect modeling for the parallelto-B ion conductive heat flux had a large impact on the plasma profiles due to the marginal
Coulomb collisionality [2]. In addition, a particle-in-cell (PIC) simulation showed that, in sucha marginal-collisionality plasma, the ion temperature anisotropy tends to be remarkable [3],indicating that an individual treatment of the parallel and perpendicular components of the ion
energy would be essential in a simulation for a DEMO reactor.
We have developed a plasma fluid model based on the anisotropic ion pressure (AIP model)[4] combined with the virtual-divertor model [5] for open-field systems. At present, the parallelto-B ion conductive heat fluxes for the parallel and perpendicular-energy components areevaluated individually by heat-flux-limiting models similar to those used in Ref. [2]. In thisstudy, the accuracy of the AIP model was investigated by directly comparing its solutions witha PIC code PIXY [6] over a range of Coulomb collisionality. The AIP model solutions werealso compared directly with the Braginskii model by using the VFA-AIP scheme [7]. It was
shown that the solutions of the AIP model were in good agreement with PIXY over the low tohigh Coulomb collisionality range, and that they were more similar to the PIXY solutions thanBraginskii-model ones. However, qualitative differences were found in the parallel-to-B ion
conductive heat flux profiles. We will also present our plan to incorporate the heat-flux
equations [8] directly into the AIP model to address this issue.
This work was performed with the support and under the auspices of the NIFS Collaboration
Research Program (NIFS23KIST050 and NIFS21KUGM164).
[1] S.I. Braginskii, Transport Processes in a Plasma, vol. 1 (Consultant Bureau, New York,1965) 205.
[2] Y. Homma, Plasma Phys. Control. Fusion 64 (2022) 045020.
[3] A. Froese et al., Plasma Fusion Res. 5 (2010) 026.
[4] S. Togo et al., Nucl. Fusion 59 (2019) 076041.
[5] S. Togo et al., J. Comput. Phys. 310 (2016) 109.
[6] K. Ibano et al., Nucl. Fusion 59 (2019) 076001.
[7] S. Togo et al., Plasma Fusion Res. 18 (2023) 1203005.
[8] W. Fundamenski, Plasma Phys. Control. Fusion 47 (2005) R163.

B-KN-2

The feasibility of using ions and charges in the medical field.
Sanae Ikehara1, 2, Ken Wakai1, Shinsuke Akita1, Takashi Yamaguchi1, Kazuhiko Azuma1,
Syota Ohki1, Nobuyuki Mitsukawa1, Hajime Sakakita2, Komei Baba3, Yuzuru Ikehara1, 2
1

Graduate School of Medicine, Chiba University1-8-1 Inohana, Chuo-ku, Chiba, 260-8670, Japanyuzuru-ikehara@chiba-u.ac.jp

2

National Institute of Advanced Industrial Science and Technology, Tsukuba, 305-8565, Japan.
3
DLC Research Institute LLC, Nagasaki, 850-0011, Japan.

The life sciences explain that information transfers in the nervous system occur through thetransmission of electrical signals and that neuronal activation and muscle contraction result
from charge and ion transfer into the cell via the activation of ion channels and receptors. Froma broader perspective, biomolecules present in the blood, such as hormones and antibodies,
their dispersion and accumulation, binding, and aggregation occur through the alterations ofcharges on functional domains of molecules and ions in living organisms. The evolution oftechnology to generate plasma at low temperatures in an atmospheric pressure environment will
not only control physiological functions such as neuronal activation and muscle contraction
caused by the transfer of electrical charges and ions into cells but also may solve Alzheimer's
disease caused by the abnormal accumulation and aggregation of biomolecule. Based on theabove understanding, the presenter, a pathologist, will present the following three studies hehas conducted to open the feasibility of using ions and charges in the medical field.
We have previously discovered the phenomenon of 1) the aggregation of proteins insolution in a dispersed state by the donation of ions and charges by using a low-temperature
atmospheric pressure plasma generator [1]. From this phenomenon, we have conceived of a
new medical device that can stop bleeding and exudation of serous fluid by coagulating blood
components, and 2) realized a minimally invasive hemostatic device that does not cause
cauterization at the treatment site [2]. Furthermore, donating ions and charges may provide ameans of overcoming the limitations of ultrastructural analysis performed using electron
microscopy, and 3) established a pretreatment
technique using plasma for scanning electron
microscopy observation [3]. Pathologists use an optical
microscope to diagnose formalin-fixed paraffinembedded thin-sections (FFPE-ts) on slide glasses but
not using scanning electron microscopy (SEM)
because of their dielectric nature. Therefore, we havedeveloped a method to change the dielectric natures of
FFPE-ts to conductive by reacting ions derived fromplasma on glass slides. Consequently, in FFPE-ts
specimens of pathological autopsy tissue of SARSCoV2 infected patients, we succeeded in seeing Fig.1,Reffered from [4] Proc Natl Acad Sci U S
damage on the tunica media of pulmonary arteries due A, 119, e2203437119 (2022).
to budding of SARS-CoV2 particles(Fig.1), which was a severe pathology of COVID-19 [4].
Notably, our plasma technology will not only allow pathologists to use SEM to diagnose viral
infections but also raise the possibility that the architecture of automated testing ofsemiconductors using SEM will carry the automated diagnosis of viral infections.
[1]
[2]
[3]
[4]

Ikehara, S., et al., Plasma Processes and Polymers, 12, (2015).
Ikehara, Y., et al., J. Photopolym. Sci. Tehnol., 26(4), (2013).
Wakai, K., et al., Sci Rep, 12, (2022).
Iwamura, C., et al., Proc Natl Acad Sci U S A, 119, e2203437119 (2022).

B-KN-3

Low-temperature and thermal plasma researchat PEwave, Walailak University

M. Nisoa, S. Kaewpawong, W. Kongsawat, R. Taleh, Karaket Wattanasit and D. Srinoum

Plasmas and electromagnetic wave research laboratory,
Walailak University: 222 Taiburi, Tasala, Nakhon si thammarat, 80160, Thailand
mnisoa@gmail.com

Applications of plasmas for agriculture, food, medical, environment,
nanotechnology and material processing have been increasing in the recent years
in Thailand. However, shortage of fundamental technologies, such as vacuum
system, high-power DC, RF and microwave power supplies and diagnostics tools,
cause difficulty for commercial scale development. The plasma andelectromagnetic wave(PEwave) research center, at Walailak University, has beendeveloped various plasma sources at low and atmospheric pressures since
2000[1,2,3,4]. In this paper, atmospheric cold plasmas produced by surface
barrier discharge and plasma jets, DC thermal plasma torch and high-power
helicon plasmas will be presented. Atmospheric cold plasmas are successfully
applied for research in food safety, shelf life extension of snacks, fruits and fish,
and induce apoptosis in cancer cells. Thermal plasma produced by DC plasma
torch has temperature more than 1200 oC will be used for gasification of medical
and plastic wastes. High-density helicon plasmas, produced by home-made 5 kW,
13.56 MHz RF power supply, has density more than 1013 cm-3 will be utilized
for plasma-material interaction study to develop materials for fusion reactor andplasma heating research.

Reference[1] M. Nisoa, D. Srinoum and P. Kerdthongmee, Development of high voltage highfrequency resonant inverter power supply for surface glow barrier discharges: Solid
State Phenomena, 107(2005), 81 – 86
[2] M. Nisoa and T. Srinoum, Characteristics of ozone production by using
atmospheric surface glow barrier discharge, Walailak J. Sci. Tech. 6(2), 283 – 292(2009)[3] P. Kerdtongmee ,1 D. Srinoum and M. Nisoa, Development of compact highvoltag e switched mode power supply for microwave plasma sources supply for low
pressure plasma, JINST, 6, 2011[4] P. Kerdtongmee, D. Srinoum and M. Nisoa, Development of a compact
permanent magnet helicon plasma source for ion beam bioengineering, Rev. Sci.
Instrum. 82, 103503 (2011)

B-I-4

Atmospheric-pressure Plasma Effects on Cancer Cells and RONS
Generation for Medical Applications
Yun-Chien Cheng1
1

Department of Mechanical Engineering, National Yang Ming Chiao Tung University
Hsinchu 30010, Taiwan
yccheng@gmail.com

We compared the effects of plasma with thermal therapy on lung cancer with malignant pleural
effusion. This study find out that the plasma can selectively kill lung cancer cells and the benign
cells remain its viability. Besides, the thermal therapy kills both cancer cell and benign cells.
To investigate what is the plasma factor that inhibits cancer cells, we investigated the effects ofplasma-generated short-lived species, long-lived species, and electric fields on skin melanoma
and basal cell carcinoma cells (A2058 cells, BCC cells) and normal cells (BJ cells, Detroit 551
cells) and found that the short-lived species do make selective inhibition to the benign andmalignant cells. The second part of my study is that we mix water aerosol with plasma jet atdownstream region makes the plasma jet generate more • OH. We designed different mixing
chambers and adjusting the water aerosol flow rate maximize the • OH generated by plasma jet
for biological applications. We also constructed an impedance matching circuit for a partialdischarge calibrated (PDC) atmospheric-pressure plane-to-plane DBD equivalent circuit. The
last part of my work is that we used machine learning to distinguish the discharge current ofdifferent plasma. The plasma discharge can be different depending on the conditions, and theresulting discharge current has quite different electrical features. Hence, a real-time and costeffective diagnosis of atmospheric-pressure plasma discharge can be possibly provided via
current classification with deep learning model.
The reactive radical such as .OH can penetrate a medium for limited thickness. Thisphenomenon can be used to control the concentrations of such radicals. By controlling the
thickness between cells and water surface, we can treat cancer cells with different
concentrations of the reactive radicals. By adding agarose gel on surface, we applied only
electric field but no RONS on cells. By comparing experimental results, we can get the effectsof short-life RONS, long-life RONS and electric field on cancer cells. relation between the PBS
thickness and penetrated .OH concentration. We observed that .OH concentration decreased
with increasing PBS thickness. The maximum penetration depth of .OH was about 0.6 mm. In
the SLE experiment, we used 0.2 mm and 0.5 mm as the experimental parameter. In the LE
experiment, we used 1.4 mm as the experimental parameter. Fig. 4 showed that the The viabilityof normal skin cells was not affected by the treatments of plasma and the electric field generated
by plasma. Fig. 5 showed that the viability of cancer cells was not affected by the electric field
and the treatments of plasma (1.4 mm), but decreased with water-layer thickness (i.e. theincrease of .OH concentration). In this work, an experimental setup was designed to be used toinvestigate the effects of CAP generated short-life RONS, long-life RONS and electric field on
cancer cells. We investigated the relation between the PBS thickness and penetrated .OH
concentration. In our study, plasma-generated electric field and long-life RONS did not affected
cells, while the short-life RONS has selectively damage on cancer cells.
[1] R.B. Gadri, R.J. Roth, T.C. Montie et al., Surface and Coatings Technology, 131, 528-541(2000).
[2] A. Mishra, P. Tummala, A. King et al., Tissue Engineering Part C: Methods, 15, 431-435.
(2009).
[3] S. Mirpour, H. Ghomi, S. Piroozmand, M. Nikkhah, S.H.Tavassoli, S.Z. Azad, IEEE
Transactions on Plasma scienceB-I-5

Effect of accumulated charge
on the dynamics of plasma bullet propagation
Jun Sup Lim1 and Eun Ha Choi2
1

1

Kwangwoon University, Plasma Bioscience Research Center (PBRC)
20 Gwangun-ro, Nowon, Seoul 01897, Republic of Korea
Junsup117@gmail.com

Kwangwoon University, Electrical and biological physics department
20 Gwangun-ro, Nowon, Seoul 01897, Republic of Korea

Dynamics of plasma behavior is interesting field in the atmospheric pressure plasma jet. In
the atmospheric pressure capillary plasma jet, initial plasma bullet generated between theelectrodes and pass through the grounded ring region toward the gas exhaust nozzle. Although,plasma bullet escaped from the high electric field region between the electrodes, it continues topropagate as a streamer to the nozzle of the gas outlet. In this experiment, the guided capillary
tube which consists of dielectric material can be accumulate the charge from the discharge
phenomena with modified sinusoidal waveform of voltage.
The electric field resulting from the charge accumulation on the inner dielectric wall andresidual charge on the discharged space could be affect to the propagating plasma bullet for
their kinetic energy.[1] In this report, we applied the bipolar and unipolar voltage of sinusoidal
wave for the separation of accumulated charge by pre-ionization of opposite polarity, and report
the effect of charge accumulation to the propagating plasma bullet behavior. In the results ofthese separation showed the changes of breakdown voltage of discharge and plasma bullet
shape in this experiment.

[1] J. Li, B. Lei, J. Wang, B. Xu, S. Ran, Y. Wang, T.
Zhang, J. Tang, W. Zhao and Y. Duan, Commun. Phys.,
4, 64 (2021)

Fig. 1: Plasma bullet propagation
with voltage polarity

DX-KN-1

Ion flux reduction factor at the sheath edge as a function of ion-neutral
collisions in low temperature Ar or He DC plasmas
Young-chul Ghim and Yegeon Lim

Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Scienceand Technology, Daejeon, S. Korea

We expect a reduction of ion flux toward a plasma boundary as the ion-neutral collisions
increase in partially ionized low-temperature plasmas. Nevertheless, experimentallyquantifying how much it will be is a challenging task, while there exists a recent report basedon particle-in-cell simulations [Beving et al., Plasma Sources Sci. Technol. 31 084009 (2022)].
As a complementary effort to such a numerical study, we have performed experiments withsystematic parameter scans aimed at directly inferring the reduction factors in ion flux causedby the collisions. DC Ar or He plasmas are generated in a multidipole chamber with different
gas pressures to control the collisionality and with various discharge currents to investigate theion flux reduction factor in a wide range of the plasma conditions. In this work, we discuss thesimilarities and discrepancies between the experimentally obtained ion flux reduction factor
and the numerical results.

This work was supported by National Research Foundation of Korea (NRF) funded by Ministryof Science and ICT, Grant Nos. RS-2022-00155917 and No. 2021R1A2C2005654.

DX-I-9

Quantification of Causality Among Frequency Modes in Linear Plasma
Using Vector Autoregressive Models
Fumikazu Miwakeichi1 and Makoto Sasaki2
1

Department of Statistical Science, The Institute of Statistical Mathematics,
Tachikawa, Tokyo 190-8562, Japan
miwake1@ism.ac.jp

2

Nihon University, College of Industrial Technology, Chiba 275-8575, Japan

Linear plasmas exhibit a large number of frequency modes (Fig.1). The mechanisms bywhich these modes emerge and how they interact with each other are not fully understood. To
investigate the interaction between modes, we employed a vector autoregressive (VAR) model.
This model allows for a more detailed and quantitative understanding of causal relationships
between modes, and in this study we constructed both a full model that considers all variables(modes) and a reduced model that excludes certain modes. By comparing the Akaike
information criterion for these models, we were able to assess significant causal relationships
between modes (Fig.2). We found that the combination of modes with a causal relationshipchanges under different pressure conditions.
In the presentation, we will further introduce methods for model selection and techniques
for data preprocessing.

Fig.1:(a) 2D representation of cylindrical plasma data(b) Fourier mode decomposition over timeFig.2:
Significant causality between modes through thecomparison of the full model and reduced model
constructed by the VAR model.

DX-I-10

Basis function analysis technique for the two-dimensional structure offluctuation in magnetized plasma
K. Yamasaki1, A. Fujisawa2, Y. Nagashima2, C. Moon2, Y. Kawachi3, D. Nishimura2,
T-K. Kobayashi2, S. Inagaki4, M. Sasaki5, Y. Kosuga2, T. Yamada6, and N. Kasuya2
1

Graduate school of Advanced Science and Engineering, Hiroshima University
Higashihiroshima, Hiroshima 739-8527, Japan
kotaro-yamasaki@hiroshima-u.ac.jp
2

Research Institute for Applied Mechanics, Kyushu University
Kasuga, Fukuoka, 816-8580, Japan.
3

Department of Electronics, Kyoto Institute of Technology
Kyoto, Kyoto, 611-0011, Japan
4

Institute of Advanced Energy, Kyoto University
Uji, Kyoto, 611-0011, Japan

5

Department of Electrical and Electronic Engineering, Nihon University
Narashino, Chiba, 275-8575, Japan
6

Faculty of Arts and Science, Kyushu University
Fukuoka, Fukuoka, 819-0395, Japan

Fluctuations are a crucial player in heat and particle transport in magnetized plasmas.
Recent studies have revealed that the fluctuations emerging from different free energy sources,
such as the gradient of density and flow, can interact with each other and coexist at different
radial locations [1,2]. These results indicate the necessity of entire and simultaneous plasma
observation to improve the understanding of fluctuation-induced transport. For this purpose,
we have developed tomography systems to observe two-dimensional structure of fluctuationsin the linear magnetized plasma device PANTA. This enables us to obtain the temporal
evolution of the emission intensity profile of the whole cross-section of the linear magnetizedplasma.
Since the reconstruction data is huge, an efficient analysis method is required to manage thedata that is composed of various fluctuations with a wide range of frequency and wavenumber,
together with intermittency. For the cylindrical geometry, we developed a basis function
decomposition technique, called Fourier-Rectangular Function (FRF) analysis [3], whichallows us to obtain the temporal and radial
profile of the amplitude and spatial phasefor each azimuthal mode.
An example of the FRF analysis on
the tomographic reconstruction data isshown in Figure 1. The FRF analysis
revealed that the nonlinearly coupledfluctuations show different spatial andtemporal behavior. In this talk, we discuss
the details of the FRF and further analysis
results, including the spatio-temporal Figure 1 The two-dimensional spatial structureof nonlinearly coupled fluctuation and temporal
behavior of the nonlinear coupling.
References
1. T. Kobayashi, et al., Phys. Plasmas 23, (2016).
2. M. Sasaki, et al., Phys. Plasmas 24, 112103 (2017).
3. K. Yamasaki, et al., J. Appl. Phys. 126, 043304 (2019)evolution of the amplitude of each modes
obtained by the tomographic reconstruction
data and FRF analysis.

DX-I-11

Applications of conditional sampling techniqueto time series of experimental plasma data
Yuichi Kawachi
Department of Electronics, Kyoto Institute of Technology
Matsugasaki, Sakyo Ward, Kyoto 606-8585, Japan
kawachi@kit.ac.jp

Various time series analyses have been established to extract plasma dynamics, which is
crucial for controlling plasma behavior. The widely used Fourier analysis assumes that theobserved data consists of stationary periodic waves and provides time-averaged information.
However, nonlinear plasma dynamics often exhibit quasi-periodic or intermittent features,such as blobs, edge-localized modes (ELMs), and various turbulent phenomena. Fourier
analysis is often inadequate for comprehending such behaviors.
As an alternative method to analyze quasi-periodic phenomena, the conditional samplingtechnique has been developed and applied extensively [1]. This technique involves digitalprocessing akin to a lock-in amplifier. Initially, the method detects the emergence timingof the target phenomena from a reference signal. Then, based on this timing, other timeseries data are resampled. Finally, the resampled data undergo statistical analysis. Thisapproach is simple yet widely applicable. For instance, it can enhance time resolution inmeasurements and data analysis when dealing with low time resolution data.
The conditional sampling technique offers flexibility in detecting the target phenomena
and analyzing the resampled data. In the former case, the conventional approach has been
to detect phenomena by setting a threshold for large-amplitude and intermittent events[2].
However, a recent method has emerged for detecting quasi-periodic and sinusoidal
waveforms. The latter method, commonly used, involves simple averaging, thoughcombinations with linear regression and Fourier analysis have also been explored[3].
This presentation will outline the analysis procedure flow for the conditional samplingtechnique and highlight its applications.
[1] G. Fuchert et al., Plasma Phys. Control. Fusion 55, 125002 (2013).
[2] S. Inagaki et al., Plasma Fusion Res. 9, 1201016 (2014)[3] Y. Kawachi et al, Physics of Plasmas 28, 112302 (2021)

Fig. 1: An example of the conditional sampling procedure.

DX-I-12

Multiple correlation analysis of nonlinear dynamics in plasma turbulence
Takuma Yamada1, Makoto Sasaki2, Hiroyuki Arakawa3, Kosuke Kikuta4,
Takashi Nishizawa5, Chanho Moon5, Yoshihiko Nagashima5,
Yusuke Kosuga5, Naohiro Kasuya5, and Akihide Fujisawa5
1

Faculty of Arts and Science, Kyushu University, Nishi-ku, Fukuoka 819-0395, Japan
takuma@artsci.kyushu-u.ac.jp

College of Industrial Technology, Nihon University, Narashino, Chiba 275-8575, Japan
Faculty of Medical Sciences, Kyushu University, Higashi-ku, Fukuoka 812-8582, Japan
4
Interdisciplinary Grad. Sch. of Engineering Sciences, Kyushu University, Kasuga, Fukuoka 816-8580, Japan
5
Research Institute for Applied Mechanics, Kyushu University, Kasuga, Fukuoka 816-8580, Japan2

3

Meso-scale structures such as streamers and zonal flows are produced by nonlinear
interaction between microscopic drift wave turbulence in fusion plasmas. Since these structures
significantly influence the plasma radial transport, to study the nonlinear dynamics of mesoscale structures is important in plasma physics and fusion reactors.
By using the linear plasma device in Kyushu University, our group succeeded in finding thestreamer structure for the first time [1]. The cross-sectional structures of the streamer, its
mediator mode, and carrier drift waves were revealed by multiple correlation analysis [2].
While the streamer structure and carrier drift waves were radially elongated, the mediator mode
had a node in the radial direction. Additionally, the axial dimensional research revealed thatwhile the carrier drift waves had an axial mode number one (propagation direction from the end
to the source), the streamer and mediator were revealed to have an axial mode number zero [3].
To compare the observed meso-scale
structures with theoretical and numericalstudies more precisely in the phase space,local information of the wave number isrequired. In this study, we tried to observe thelocal wave number (poloidal mode numberm) of plasma turbulence. Furthermore, local
information of the results of multiple
correleation analysis were obtained.
Figure 1 well shows that when thestreamer exists, the amplitude of mode
number three (one of the carrier waves) is
poloidally localized and the localized regionis rotating in the poloidal direction with thefrequency of 1.2 kHz, which is the same
frequency with the rotation of streamer.
[1] T. Yamada et al., Nat. Phys. 4, 721 (2008).
[2] T. Yamada et al., Phys. Rev. Lett. 105,
225002 (2010).
[3] T. Yamada et al., J. Phys. Soc. Jpn. 87,
034501 (2018).

Fig. 1: Time evolution of the m = 3 amplitude.
Window function is applied in the poloidal
direction. The windows are phase shifted for–π/2, –π, –3π/2, compared to the top figure.

S-KN-4

Beam-assisted Atomic Layer Etching
Doo San Kim†, Yun Jong Jang†, Ji Eun Kang†, and Geun Young Yeom†‡*†

School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon
16419, Republic of Korea‡
SKKU Advanced Institute of Nano Technology (SAINT), Sungkyunkwan University, Suwon
16419, Republic of Korea*E-mail: gyyeom@skku.edu

Abstract
The atomic layer etching technology is currently being researched in various ways by academia, theresearch community, and semiconductor equipment/device companies. It is expected to be the nextgeneration precision etching technology due to its characteristics of low damage, high selectivity,
low aspect ratio dependent etching (ARDE), and high uniformity. In this presentation, we used aremote plasma source-type energetic particle beam source to etch various semiconductor materials(silicon, oxides, III-V, 2D materials) and evaluated their properties. We aim to summarize the research
results in this presentation. Neutral beams do not cause charging effects due to ions, and electron
beams have minimal momentum exchange due to ion collisions, reducing the potential for material
damage during etching. In this presentation, we intend to provide the results of etching ofsemiconductor materials using these energetic particles.

S-KN-5

Past, Present, and Future Plasma Solutions to Semiconductor Challenges
Sang Hoon Ahn

Semiconductor R&D Center, Semiconductor, SAMSUNG ELECTRONICS Co., Ltd.
San #16 Banwol-Dong, Hwasung-City, Gyeonggi-Do 445-701, Korea
sanghoona.ahn@samsung.com
Plasma has been used as a key enabling technology for thin film deposition and etch in thesemiconductor device manufacturing since the birth of the semiconductor devices. The traditional
semiconductor device trend can be characterized by 2D down-scaling but 3D up-scaling. The
traditional scaling continues to reduce the size in 2D, but it keeps increasing in 3D to ensure thedevice or interconnect density improvement every node. Nonetheless, these trends drive the processtemperature down as well as enhances the structural aspect ratio very high, which, in turn, requires
increasingly high gap-fill capability and highly conformal deposition together with high integrity
etch. This paper will review how deposition plasma technology has evolved to address thesemiconductor device challenges such as high quality film at low temperature, high aspect ratio
gapfill, highly conformal deposition, low k dielectrics, and wiggly lines over the time. Plasma
enhanced chemical vapor deposition (PECVD) was introduced to deposit high quality dielectrics at
relatively lower temperature than 500C. Typically, films deposited by PECVD has a poor step
coverage with large overhang, creating voids. This inability to fill up the trenches resulted in inventing
high density plasma CVD which has both deposition and etch components simultaneously. HDPCVD
have been applied to diverse gap-fill applications for many nodes. As HDPCVD has run out of its
steam at an advanced node, flowable CVD has adopted the remote plasma for reactant gases while
the CVD precursors are introduced to a reactor without being exposed to plasma. Its gapfill
capability improved dramatically. Dielectric film qualities can also be engineered by an appropriate
selection of the deposition plasma frequency. For example, at the superfine line pitch, patterned line
can be wiggly under the compressive stress. VHF PECVD can boost its density as well as its stressin a tensile direction to overcome the risk of wiggly line. Pulsed PECVD can also reduce the sticking
coefficient of the CVD precursor, boosting its deposited film step coverage up to 95% at thepattern. Mixed plasma frequency can be used as a knob to boost the deposition rate as well as thefilm density. Throughout the history of the plasma application to semiconductor, the engineering ofdielectric film properties by plasma have been nicely demonstrated to address diverse challenges ofever scaling semiconductor devices. Moving forward, the mega trend is expected to continue inlowering temperature, increasing higher aspect ratio, and improving higher qualities (k, stress) andthere are even more opportunities for plasma technology to contribute to the semiconductor
applications.

S-I-2

Plasma-enhanced atomic layer processing for semiconductor processing
Satoshi Hamaguchi, Tomoko Ito, and Kazuhiro Karahashi
Graduate School of Engineering, Osaka University, Osaka, Japan
Email: hamaguch@ppl.eng.osaka-u.ac.jp

The most advanced generation of semiconductor devices that are already in mass production(as of mid-2023) is said to be 3nm technology node devices. As the mass production of thesubsequent generations of semiconductor devices, i.e., 2nm node devices and beyond, is alreadyin sight and new and complex device structures such as those for gate-all-around field effecttransistors (GAA-FETs) need to be mass-produced, highly innovative plasma processing
techniques with atomic-scale accuracy must be developed expeditiously and cost-effectively.
For this purpose, a large part of the conventional try-and-error approach for processdevelopment must be replaced with more logical approaches based on a better understandingof the fundamental mechanisms of surface processing. In this presentation, recent analyses ofplasma-material interactions based on atomic-scale numerical simulations and surface reaction
experiments will be discussed with atomic-layer etching (ALE)1,2,3 and atomic-layer deposition(ALD)4 as examples.
References
1. E.T.C. Tinacba, et al., J. Vac. Sci. Technol. A39, 042603 (2021).
2. A. Hirata, et al., Jpn. J. Appl. Phys. 62 SI1015 (2023).
3. A. H. Basher, et al., J. Vac. Sci. Technol. A38, 052602 (2020); A39, 057001 (2021).
4. T. Ito, et al., Jpn. J. Appl. Phys.61, SI1011 (2022).
5. K. Arts, et al., Plasma Sources Sci. Technol. 31, 103002 (2022).

GN-I-10

Adsorptive removal of cationic and anionic dyes using nanocomposite of graphene
oxide/zinc oxide from aquatic environment.
Ghayas Uddin Siddiqui*, Adnan Ali, Youn Sun Mok
Department of Chemical Engineering, Jeju National University, Jeju 63243, Republic of Korea.
gsiddiqi@jejunu.ac.kr

Abstract
Today water contamination has become one of the most serious problems due to discharge ofhazardous dyes into the aquatic environment. There are numerous methods to remove those dyes,
but adsorption is considered one of the most facile and feasible methods to remove the pollutantsfrom the water. Researchers have been making many efforts to develop and synthesize adsorbents
that can eliminate contaminants from water but selecting an adsorbent is difficult task becausesome adsorbents can only remove cationic dyes and some can remove only anionic dyes. This
study aimed to remove the cationic (Methylene Blue) and anionic (Eosin Y) dyes using ananocomposite of graphene oxide and zinc oxide. Results showed that 0.23 mg/ml GO/ZnO
nanocomposite adsorbed 0.1 mg/ml EY and 0.04 mg/ml MB dyes simultaneously from the aqueous
solution in 10 and 15 minutes respectively. These are the appreciable results showing highly
efficient removal of pollutants using GO/ZnO nanocomposite via adsorption method.

Figure 1. a) ZnO nanoparticles used for the adsorption, b) graphene oxide synthesized by modified Hummer’s method

GN-I-11

3D-Graphene Networks: Synthesis and Applications
Mineo Hiramatsu1, Keigo Takeda1, Hiroki Kondo2 and Masaru Hori2
1

Department of Electrical and Electronic Engineering, Meijo University
1-501 Shiogamaguchi, Tempaku, Nagoya 468-8502, Japanmnhrmt@meijo-u.ac.jp
2

Center for Low-temperature Plasma Sciences, Nagoya University
Furo-cho, Chikusa, Nagoya 464-8603, Japan

3-dimensional (3D) graphene network called as carbon nanowalls (CNWs) and verticalgraphenes represents an aggregate of vertically standing graphenes. CNWs and related sheet
nanostructures are composed of self-supported few-layer graphene sheets with open boundaries,
standing almost vertically on the substrate. CNWs are characterized by large specific surface
area and space surrounded by vertical graphene sheets. The wall maze-like architecture or
disordered honeycomb structure of CNWs with large-surface-area graphene planes could beapplied as electrodes for energy storage devices and electrochemical sensors as well as scaffold
for cell culturing. CNWs have beengrown using various CVD methods
employing CH4 and H2 mixtures on avariety of heated substrates [1]. The
morphology of CNWs depends on
the source gas mixtures, pressure,process temperature as well as thetype of plasma used for the growth of
CNWs. Isolated nanosheets, verticalmaze-like structure, highly branched
type, and a kind of porous film havebeen fabricated. We can expect a
Fig. 1 Schematic illustration of expectedwide variety of applications based on
applications of CNWs vs. morphologies.
their structure as illustrated in Fig. 1.
In the typical case of wall maze-like CNW growth, after the nucleation, the height of CNWs
increases almost linearly with the growth period, while the thickness of each sheet andinterspaces between adjacent sheets are almost constant. From TEM observation, each sheet iscomposed of nanographene domains. These domain boundaries and graphene edges are
chemically reactive, and metal nanoparticles such as Pt nanoparticles stick selectively at thegrain boundaries and graphene edge (top of CNWs). Therefore, combined with surfacefunctionalization, CNWs can be suitable as platform in electrochemical and bio applications.
For this purpose, we have carried out CNW growth using inductively coupled plasma-enhanced
CVD with CH4/H2/Ar mixture. Moreover, CNW surface was decorated with Pt nanoparticles
by the reduction of chloroplatinic acid. Alternatively, conformal coating of CNW surface withmetal oxide nanoparticles/films such as ZnO and SnO2 was carried out using mist CVD orthermal decomposition. As examples of applications, we report the performances of hydrogen
peroxide sensor and fuel cell, where CNW electrode was used. Electrochemical experiments
demonstrate that CNWs can be promising electrode materials for electrochemical sensing,biosensing and energy conversion applications.
[1] M. Hiramatsu, M. Hori, Carbon Nanowalls, Synthesis and Emerging Applications (Springer
Verlag, Wien, 2010).

PL-7

Near-future industrial innovation
Digital transformation (DX) to Quantum transformation (QX)
Masahiro Horibe
Global Research and Development Center for Business by Quantum-AI Technology (G-QuAT),
National Institute of Advanced Industrial Science and Technology
1-1-1 Umezono, Tsukuba, Ibaraki 305-8563, Japanmasahiro-horibe@aist.go.jp

Japanese government has been serise of quantu strategy since 2020. The first strategy,“Quantum Innovation and Technology Strategy“ has been published in 2020 and forcused on
besic technical research in quantum infomation science[1]. In 2021, some of forign quantum
computing venders relased gate-type quantum computer thrugh cloud platfor. This means thatquantum R&D activities is stared to move to social imprementations. The government relased“Vision of Quantum Future Society“ in 2022[2], and “Strategy of Quantum Future Industry
Development“, as a roadmap of imprementation of quantum technology to society, in 2023[3].
In the vision and strategy, the METI decide to build new R&D center (G-QuAT) in AIST.
G-QuAT is not only focusing on research and development but also business development.
Especially, valuable applications are going to be created using quantum computing technology
and G-QuAT plans the next generation large-scale quantum computer and related system level
developments by collaborating with quantum computing venders and components suppliers. As
the results of the activities, quantum business ecosystem will be created in future.
In the case of quantum application development, G-QuAT is now starting to collaborate
with various industrial users to create new solution by quantum computing algorithms
combined with existing classical computing technology. We try to implement quantum
computing technology to materials informatics, bioinformatics, and process informatics.
Plasma process and control technology are one of valuable R&D target as quantum computing
applications.
Other activity in G-QuAT also research quantum sensing system technology to realize
accurate and precision measurements. The sensing is also support to plasma research activity.
[1] “Quantum Innovation and Technology Strategy“, Japanese government (2020).
[2] “Vision of Quantum Future Society“, Japanese government (2022).
[3] “ Strategy of Quantum Future Industry Development“, Japanese government (2023).
Research area

G-QuATR&D facility
ABCI

User Industries(1) Application

Life Science andBiotechnology(1) Application

Supercond.
Quantum devices(1) Application
Information Technology and(inc. computer architecture)
Human Factors

Silicon Qubits
Cryo-CMOS

Material and Chemistry

Large-scale
Silicon Qubits

Electronics andManufacturing
Geological Survey of Japan
National Metrology
Institute of Japan(1) Application

COLOMODE(1) Application(2) Evaluation/standards(3) Device fab.
(1) Application(1) Application(2) Evaluation/standards

Qufab

Other R&D Platform
collaboration(Physical test bed)
Material Process
Innovation Platform
FREA(Energy)
Smart factory
6G communication, etc.

Figure 1: Application development framework in AIST coordinated G-QuATPL-8Divertor detachment: Fusion plasma physics meets plasma chemistry
Detlev Reiter1
1 Heinrich-Heine-University Düsseldorf,

D-40225 Düsseldorf, Germany

reiterd@uni-duesseldorf.de

It was recognized as early as 1968 by Bo Lehnert [1] that a zone of powerful gas - plasmainteraction, formed near intensely plasma exposed surface elements, can be the key tosolving the still critical plasma surface interactions (PSI) issue for sustainable nuclear fusion
reactor operation. Today the „divertor detachment'' regime in large magnetic fusion devices(tokamaks, stellarators) is characterized by strong volumetric exchanges of particles,
momentum and energy, provided by such a gas-plasma interaction zone near target surfaces.
Computational separation of plasma chemistry from the typically only empirically known
plasma transport (intermittent or turbulent) allows to quantify the latter experimentally.
Firstly, by resorting to highly accurate atomic and molecular (AM) collision data [2]This builds on rate equation concepts well established e.g. in astrophysical and chemical
kinetics (aka: non-equilibrium collision radiative modelling). Secondly by building on thehigh standards in (kinetic) transport theory and its wide range of applications, e.g. in the
nuclear (neutronics) or radiation transfer sciences. This has meanwhile led to quite maturefusion boundary plasma (often partially “Monte Carlo” based) multi-physics and multi-scale
simulation tools [3].
It is shown that the dominant gas-plasma friction force in typical “detached divertor
conditions” is to be expected from (ro-vibrationally excited) molecule - ion collisions, rather
than from the often-quoted resonant charge exchange between fuel atoms and their ions.
In conditions relevant for the boundary region in fusion devices a high sensitivity of thefriction forces and energy exchange rates (kinetic and chemical energy exchanges between
plasma components) between the gas and plasma phases is observed. Originating from a-

combination of electron collisions via various resonant H2 anion states and the nearresonant heavy particle ion conversion channels, such as particle rearrangement or chargetransfer. The former electron collisions have recently been theoretically re-investigated andcompleted in [4] for a wide set of intermediate resonant states, with the Local Complex
Potential approach.
Direct contributions from dissociating molecules and their ions to atomic spectral lines,
typically with overlapping kinetic energy releases, complicate visible light spectroscopy.
Furthermore, quite unexpected kinetic isotope effects may arise in the D-T mixture of afuture reactor divertor plasma: This effect might be well accessible experimentally indedicated small laboratory plasma devices, e.g., when operated in H/D mixtures.
[1] B.Lehnert, Journal Nuclear Fusion 8, 173, (1968)[2] IAEA Vienna, Atomic and Molecular Data Unit, https://amdis.iaea.org (2023)[3] R.Pitts, X.Bonnin, et al., Nuclear Materials and Energy 20, 100696 (2019)[4] V.Laporta, R.Agnello et al., Plasma Phys. Control. Fusion 63, 085006 (2021)

PSLO-I-8

Verification of Birth Process of Primordial Organic Molecules in the Solar
System from Molecular Clouds using Molecular Dynamics Simulations
Hiroaki Nakamura1,2, Masayuki Murai2, Yuki Goto1, Miyuki Yajima1, Masahiro Kobayashi1,
Masahiro Katoh1,3,4, Kensei Kobayashi51National Institute for Fusion Science, 322-6 Oroshi, Toki GIFU 509-5292, Japanhhnakamura@nifs.ac.jp
2
Nagoya University, Furo, Chikusa, Nagoya 464-8603, Japan
3
Hiroshima Synchrotron Radiation Center, Hiroshima University, Higashi-Hiroshima, 739-0046, Japan
4
UVSOR Synchrotron Facility 38 Nishigo-Naka, Myodaiji, Okazaki, 444-8585, Japan
5
Yokohama National University, Tokiwadai, Hodogaya-ku, Yokohama 240-8501, Japan

The prevailing theory for the origin of lifeon the earth is that the amino acids (or more
precisely, amino acid precursors, named"garakuta molecules" [1]), that make up
proteins came from extraterrestrial sources[25]. To confirm this theory, it is necessary to
clarify the reaction pathway of how aminoacids are synthesized extraterrestrially.
The following proposal, named thebottom-up scenario, was proposed as a
candidate scenario for the synthesis reactionof amino acids. The bottom-up scenario
assumes a process in which organic dust
scattered in the vicinity of a nova that has
Fig. 1: molecular weight distribution ofreached the end of its life is incorporated into
product molecules.
a molecular cloud and reacts to become thegarakuta molecule.
The study of this reaction pathway has confirmed that amino acid precursors are synthesizedfrom small molecules through experiments using an accelerator. We attempt to corroborate thereaction in this experiment using a molecular dynamics simulation. Specifically, hydrogen,carbon monoxide, and ammonia were randomly arranged as small molecules in the ratio of
100:10:1, the temperature was raised to 1000 K, and then cooled to 10 K.
The results of the MD simulation for the 80 ps show that large molecular weight molecules
are produced, as shown in Fig. 1.
Acknowledgment: The computation was performed using Research Center for
Computational Science, Okazaki, Japan (Project: 22-IMS-C104) and Plasma Simulator of NIFS.
The research was supported by Japan Society for the Promotion of Science (Grant Nos.
JP19K14692, JP22H05131, JP23H04609, JP22K18272, JP23K03362), by the NINS programof Promoting Research by Networking among Institutions, by the NIFS Collaborative Research
Programs (NIFS22KIIP003, NIFS22KIGS002, NIFS22KISS021) and by the ExCELLS Special
Collaboration Program of Exploratory Research Center on Life and Living Systems.
[1] K.Kobayashi, et al., Astrobiology: Emergence, Search and Detection of Life (Ed.:Basiuk,
V. A.), p. 175, American Scientiﬁc Publishers, Stevenson Ranch, CA, USA (2010)。
[2] S. L. Miller, Science, 118(1953) 528.
[3] G. Schlesinger and S.L. Miller, J. Mol. Evol., 19 (1983) 376.
[4] J.E. Elsila, et. al., ACS Cent. Sci., 2 (2016) 370.
[5] C.R. Cronin, S. Pizzarello, Science, 275 (1997) 951.
[6] I. Endo, I. Sakon, et al., Astrophys. J., 917 (2021) 103.

PSLO-I-9

Angular Momentum Coupling of Tilted Gaussian Beamwith Waveguide Mode
Yoshihisa Fujita1, Hiroaki Nakamura2, Hideki Kawaguchi3 and Yuki Goto2
1

College of Industrial Technology, Nihon University,
1-2-1 Izumi, Narashino, Chiba 275-8575, Japanfujita.yoshihisa@nihon-u.ac.jp
2
National Institute for Fusion Science,
322-6 Oroshi, Toki, Gifu 509-5292, Japan3

Muroran Institute of Technology,27-1 Mizumoto, Muroran, Hokkaido 050-8585, Japan

An optical vortex is an electromagnetic wave with a spiral wavefront. Since the phase of an
optical vortex has higher degrees of freedom than that of a plane wave, applications inmeasurement and heating have been proposed. The possibility of propagating in plasmas above
the cutoff density has been suggested [1], and its application is expected. Various methods of
excitation of optical vortices have been proposed [2, 3], all of which are realized by shifting thephase of the plane wave using interaction with the medium. High-power millimeter wave isnecessary to adapt to high-temperature plasmas. When high power is used, Joule losses in themedium cannot be ignored. Therefore, this study aims to propose a new excitation method for
optical vortices.
Waveguides are used to transmit electromagnetic waves over long distances. The
superposition of eigenmodes of cylindrical waveguides with different phases can be used torepresent vortex modes such as optical vortices [4]. Nevertheless, it is difficult to excite
arbitrary eigenmodes simultaneously. Generally, a Gaussian beam is incident parallel to the
waveguide axis when exciting a waveguide mode. It is known that multiple higher-order modes
are generated when the axes are misaligned. Therefore, it would be possible to control the
excitation modes by clarifying the relationship between misalignment and higher-order modes.
By calculating the coupling between the Gaussian beam and the eigenmodes of the
waveguide, the fraction of excitation modes can be calculated. Ohkubo et al. clarified therelationship between incident angle and excitation modes by calculating couplings [5].
However, vorticity has not been evaluated. The orbital angular momentum of the Gaussian
beam is zero, but the optical vortex is not. In addition, the oblique incidence of the Gaussian
beam will most likely have orbital angular momentum. Therefore, the purpose of this study is
to clarify the angular momentum coupling in a misaligned waveguide.
Details will be presented at the conference.
[1] T. I. Tsujimura et al., Phys. Plasmas 28, 012502 (2021).
[2] H. Chung et al., Sci Rep 10, 8289 (2020).
[3] B. He et al., J. Opt. Soc. Am. B 38, 1518 (2021).
[4] D. Mao et al., APL Photonics 4, 060801 (2019).
[5] K. Ohkubo et al., Int. J. Infrared Milli. Waves 18, 23 (1997).

PSLO-I-10

A simple method for modifying the surface morphology of various
semiconductors and its application in random lasing
Quan Shi1, Hideki Fujiwara2, Shin Kajita1, Ryo Yasuhara3, Hirohiko Tanaka4, Noriyasu
Ohno4, Hiyori Uehara3
1

The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561, Japan
shi.quan@edu.k.u-tokyo.ac.jp
2
Faculty of Engineering, Hokkai-Gakuen University, 1-1, Nishi 11, Minami 26, Chuo-ku, Sapporo 064-0926,
Japan
3
National Institute for Fusion Science, 322-6, Oroshi-cho, Toki 509-5292, Japan
4
Graduate School of Engineering, Nagoya University, Nagoya, 464-0863, JapanAs the development of high technology progresses, the social demand for semiconductor
products has been expanding. The demand for nano/micro-meter surface modification that canbe applied to a wide range of semiconductors has increased. However, specific structures orpatterns are not always necessary for all conditions. Therefore, it is necessary to look for a
simple method to fabricate structures on semiconductors.
This study introduces a one-step method called co-deposition etching (CoED).
Semiconductors substate was exposed in noble gas plasma such as helium (He) and argon (Ar),as shown in the experimental step in figure 1(a). Molybdenum impurities were introduced froma sputtering wire with bias. Structures are formed mainly due to the preferential sputtering after
heavy impurities deposited on the substrate. This idea came out from the formation of cone
structures on silicon after He plasma irradiation, which was because of the presence of heavy
impurities. This method can be applied to various semiconductors, such as gallium arsenide,
germanium, zinc selenide, and gallium nitride, as long as the sputtering rate of impurity species
is smaller than that of the substrate. Besides, characteristics of structures, such as size, height,
and density, can be controlled by the deposition rate of impurities, which increase the possibility
for application.
One of the successful examples is performing random lasing on GaN treated by CoED. As
shown in figure 1(b-c), an emission at 365 nm with a narrow linewidth can be observed fromthe GaN surface with particles of micrometer size, excited by a UV pulse laser. The lasing
intensity increasing with the size of structures.

Fig. 1. (a) Schematic of the experimental setup of the co-deposition etching (CoED) method.
(b) Topography of GaN treated by CoED. (c) Spectrum of random lasing from GaN excited bya pulse laser with a wavelength of 355 nm. (d) Correlation between the intensity of lasing andsize of structures on GaN.

B-I-6

Applications of Cold Plasma Technology in the Agri-food Industry
Roopesh Mohandas Syamaladevi (M. S. Roopesh)11

Food Safety & Sustainability Engineering Lab
Department of Agricultural, Food & Nutritional Science
University of Alberta
Edmonton, Alberta, T6G 2P5, Canada
roopeshms@ualberta.ca

Cold plasma (CP) technology has gained a huge interest in the agriculture and food industry
recently. The applications of cold plasma range from seed germination to disinfection in theagri-food sector. This presentation will focus on some of the most researched and emerging
applications of cold plasma in the agri-food sector.
This presentation also aims to introduce some of the research works conducted at the
University of Alberta on cold plasma applications in seed germination and plant growth as well
as for disinfection. In the seed germination research, details on germination improvement ofcold plasma treated seeds (e.g., peas, lentils) and greenhouse trial results will be discussed.
In the disinfection research, the effectiveness of plasma activated water bubble technology
with different hydrodynamic flow regimes on the inactivation of microbial biofilms insidepipelines will be discussed. The presentation ends with an overview of the activities of certain
companies working on the scale-up of cold plasma technologies in the food and agriculture
sectors.

B-I-7

Behavior of Gas Flow and Characteristics of Atmospheric Pressure Plasma
Jet for Bio-Applications
Hiromasa Yamada1
1
National Institute of Technology, Nagano College
716 Tokuma, Nagano city, Nagano 381-8550, Japanh_yamada@nagano-nct.ac.jp

Atmospheric pressure plasma jets (APPJs) are plasmas ~100 mm in diameter and ~101 mm inlength that are generated at atmospheric pressure using noble gases as the working gas. The
APPJ can be easily generated using a low-cost power supply without the constraints of achamber. It is also possible to generate plasma with a low gas temperature that can be touchedby hand, and is being applied to various fields such as hemostasis, cancer treatment, and othermedical applications. APPJ generated in a working gas stream generates reactive species, which
are important in many bio-applications, by mixing with ambient air and being transported by
the working gas stream. In addition, plasma generation has been reported to promote turbulencein the working gas stream (jet stream) [1]. Such an effect of plasma generation on the gas flow
also affects the plasma generation path, i.e. the plasma size and the generation and transport ofreactive species. Therefore, it is important to understand the relationship between the APPJ andthe gas flow in order to effectively promote each bio-application by controlling the size of the
APPJ and efficiently transporting reactive species.
The effect of plasma generation on the gas flow, such as increased turbulence, is caused by
the action of charged particles (ions and electrons) accelerated by an electric field on the neutral
particles that make up the gas flow. However, the electric field acting on the charged particles
is spatially complex, being formed between the plasma itself, the high-voltage electrodes used
to generate the plasma, the surrounding equipment, etc. Therefore, the understanding of themechanism of the effect of plasma generation on gas flow in APPJ is not fully understood. In
this study, we analyzed the effect of the electric field on the working gas flow in the APPJ byplacing external electrodes between the generated plasma from above and below and applying
an external electric field with a constant direction and magnitude in space and time to the plasma
to better understand the behavior of charged particles. The presentation will discuss the resultsfor other conditions and the relationship to plasma properties such as emitting species andtemperature.
[1]

H. Yamada, et al., Jpn. J. Appl. Phys., Vo. 55, No. 1 (2016), pp. 01AB08-1 - 01AB08-5.

B-I-8Environmental control for plant growth and preservation using
high-voltage pulsed discharges
Katsuyuki Takahashi1 and Koichi Takaki1,2
1Faculty of Science and Engineering, Iwate University
4-3-5, Ueada, Morioka, Iwate, 020-8551, Japanktaka@iwate-u.ac.jp
2Agri-Innovation Center, Iwate University
3-18-8, Ueada, Morioka, Iwate, 020-8550, Japan

Agricultural applications of high-voltage pulsed discharges have been widely investigatedand have become one of the most attractive research topics in plasma science [1]. Atmosphericpressure plasma can produce various types of chemical active species, which have various
effects on the cell membrane of bacteria, activity of a living plant body and chemical structureof organic compounds.
As a production process of fruits and vegetables, hydroponics, which is the method of
growing plants without soil using nutrient solution, has been widely used. In hydroponics, thenutrient solution is re-circulated in a closed system in to reduce the cost and the environmental
load. In the system, plant diseases caused by microbial contamination of the artificial nutrient
solution rapidly spread in the circulation system and cause serious damage to the entire plant.
During the entire period of plant growth, contamination with pathogens can never be excluded,
since the pathogens are introduced in the nutrient solution via the irrigation water supply.
Therefore, the nutrient solution should be remedied by continuous water treatment system
operation during the cultivation period.
In transportation and preservation of fruits and vegetables, it is desired to store several kindsof productions in one place because it can reduce the cost due to the effective utilization of
space. In these cases, ethylene (C2H4) is responsible for the changes in texture, softening andcolor, depending on how sensitive the plant is to C2H4.
C2H4 is thought of as an aging hormone in plants. Since
ethylene sensitive fruits such as persimmon and the others
naturally emit a lot of C2H4 to the air such as apple are
loaded together in one container, ethylene sensitive fruits
should be kept in an extremely low C2H4 level duringtransportation.
In this study, water and gas treatment systems using
non-thermal plasmas generated by pulsed high voltages
are developed for practical use in hydroponic cultivation Fig. 1: System for treatment ofas shown in Fig. 1 [2,3] and preservation of fruits and nutrient used in hydroponics.
vegetables as shown in Fig. 2 [1]. These system showshigh performance for improving the environment of
production and preservation of fruits and vegetables.
[1] K. Takaki, K. Takahashi, D. Hamanaka, R. Yoshida,
and T. Uchino, Jpn. J. Appl. Phys., 60, 010501 (2021),.
[2] K. Takahashi, Y. Saito, R. Oikawa, T. Okumura, K.
Takaki and T. Fujio, J. Electrostat., 91, 61-69 (2018),
61-69.
[3] K. Takahashi, S. Kawamura, R. Takada, K. Takaki andT. Fujio, J. Appl. Phys., 129, 143301 (2021).

Fig. 2: Ethylene removal
system for practical use
installed in container.

DX-I-13

Simultaneous inference of multiple plasma parameter profiles by utilizing
transport properties
Takashi Nishizawa
Research Institute for Applied Mechanics, Kyushu University,
Kasuga, 816-8580, Japant.nishizawa@riam.kyushu-u.ac.jp

Numerical techniques for the computation of a posterior distribution ease restrictions on
inference models, and multiple plasma parameters can be simultaneously inferred with detailed
modeling of uncertainties[1]. In addition, data that depend on multiple parameters in a complex
fashion can also be utilized[2]. This contribution reviews the frameworks that further expand
the capability of inference by including transport properties in plasmas.
In addition to the smoothness conditions, the particle conservation law given by a transportmodel provides a prior belief. Specifically, sets of plasma parameter profiles that satisfy theparticle conservation law are likely to be true. This information can be utilized as the priorbelief within the Bayesian frame. Ref[3] employs a prior probability function that takes large
values when the particle source and sink terms are balanced by the divergence of a diffusive
particle flux. Through synthetic data analyses, it is shown that one-dimensional profiles of theelectron density, electron temperature, and neutrals can be inferred even when only a few line
integrated quantities are observable. Furthermore, if local measurements of plasma parameters,e.g. Thomson scattering diagnostic, are available, the diffusion coefficient can be treated as
unknown, and estimated together with the other plasma parameters.
The second example[4] considers the measurements of the diffusion coefficient and theconvection velocity of impurities in a tokamak plasma. In this case, the profiles of thesetransport coefficients for given source and sink can be obtained by solving linear equations. By
taking advantage of this low computation cost, the transport coefficients can be directly inferredfrom data without considering the profiles of
impurities. As is the case with conventional
techniquesfor
impuritytransport
measurements, this inference problem is illconditioned. To address this issue, a nonparametric Bayesain approach is employed. In
this framework, all spatial points that representsmooth profiles have their own degrees of
freedom. Therefore, all solutions that areconsistent with data and prescribed smoothness
conditions can be considered. The red solidlines shown in Fig. 1 are the 50% percentitles of
those solutions.
[1] S. Kwak, et.al, Nucl. Fusion, 60, 046009(2020).
[2] C. Bowman, et.al., Nucl. Fusion, 62, 045014(2020).
[3] T. Nishizawa, et.al., Phys. Plasmas, 28, 032504(2021).
[4] T. Nishizawa, et.al, Nucl. Fusion, 62, 076021(2022).

Figure 1. Profiles of the impurity
diffusion coefficient (top) andconvection velocity (bottom) obtainedby the non-parametric inference.

DX-I-14

Information Thermodynamics of Plasma Wave Turbulence
Eiichirou Kawamori
Institute of Space and Plasma Sciences, National Cheng Kung University
1, Ta-Hsueh Road, 70101 Tainan, Taiwan
kawamori@isaps.ncku.edu.tw

Information thermodynamics treats information and thermodynamic functions in the same
framework of thermodynamics, enabling to decrease entropy using information (i.e. exchange
between thermodynamic entropy and information entropy) without any energy cost.
Historically, this idea was initiated by J. C. Maxwell, who considered a gedankenexperimentthat a thermodynamic system immersed in a heat bath is measured and manipulated by an
external intelligence called Maxwell daemon to decrease the entropy. With appropriate usageof information perpetual heat engines of the second kind can be realized, that is, extraction ofwork from the heat bath [1].
Turbulence is a highly energy-rich state sustained by steady energy injection. However,the stored energy in turbulence cannot be extracted as work, but rather dissipated as heatbecause of its highly incoherent property. This is analogous to the prohibition of perpetual heatengines of the second kind referred to as the second law of thermodynamics. However, with theuse of information on turbulence and thermodynamics, the extraction of coherent work fromturbulence may be possible. This study aims at the verification of the theory of information
thermodynamics of plasma wave
turbulence employing numericalexperiments, demonstration of
extraction of coherent work fromturbulence, and an analogous
perpetual heat plasma engine of thesecond kind using the theory.
The developed code simulates
one-dimensional
(1D)
wave
turbulence and traces the motion andtrajectory of a particle immersed in Fig. 1. Time evolution of kinetic (red), potential (blue), andtotal (black) energies of the particle in the K-S turbulence forthe turbulence. The particle motion the cases of (left) no feedback control application and (right)
is governed by the electrostatic the feedback control application, respectively.
potential of the wave turbulence.
Wave turbulence applied this time is Kuramoto-Sivashinsky (K-S) turbulence with a periodic
boundary condition. We manipulate the phase of the wave turbulence according to a protocol
based on information about the particle in the phase space. Figure 1 shows the time evolutionof kinetic (red), potential (blue), and total (black) energies of the particle in the K-S turbulence
for the cases of (left) no feedback control application and (right) the feedback control
application using the measured information about the particle, respectively. The kinetic energy
is saturated at ~ 3.0 and the particle shows a kind of Brownian motion after t ~ 400 when no
feedback control is applied (left). On the other hand, when the feedback control is applied, thekinetic energy of the particle is monotonically increased in time as shown by the black in Fig.
1 (right), indicating an extraction of coherent work from the turbulence.
[1] Juan M. R. Parrondo, et al., Nature Physics 11, p.p. 131–139 (2015).

DX-I-15

On the mechanism of high-speed SiO2 etching using hydrogen fluoridecontained plasmas at cryogenic temperature
Shih-Nan Hsiao1, Makoto Sekine1, Nikolay Britun1, Michael Kin-Ting Mo1, Yusuke Imai1,
Takayoshi Tsusumi1, Kenji Ishikawa1, Yuki Iijima2, Masahiko Yokoi2, Ryutaro Suda2,
Yoshihide Kihara2 and Masaru Hori1
1

Center for Low-temperature Plasma Sciences
Furo, Chikusa, Nagoya 464-8603, Japan
2

Tokyo Electron Miyagi Ltd.
Techno-Hills, Taiwa-cho, Kurokawa-gun, Miyagi, 981-3629, Japan(Corresponding authors: Shih-Nan Hsiao, e-mail: hsiao@plasma.engg.nagoya-u.ac.jp)

Plasma etching is a key process in the manufacturing of semiconductor integrated circuit
devices. Conventionally, the reactive ion etching (RIE) processes rely on the formation ofradicals or ions which are transported or accelerated by plasma sheath to react with the surface
being etched. Recently the low-temperature or cryogenic temperature etching has drawn muchattentions for the structure with high aspect ratio contact, owing to its unique feature that theradicals and etchants can physisorbed on the surface. However, the mystery for the dramaticenhancement of SiO2 using CHF3 plasma at cryogenic temperature still remains unsolved [1].
In this work, the dependence of etch rate (ER) of SiO2 on substrate temperature (Ts) using CF4
plasma mixed with H2 additive (H2 percentage ranged from 30 to 70 %) was investigated. A
home-made reactor equipped with a dual frequency capacitively coupled plasma was used. The
Ts was controlled by circulant cooling system from 20 to −60 C. An in situ spectroscopic
ellipsometry (SE) and Fourier Transformation infrared spectroscopy (FTIR) was implemented
to the reactor to provide real time etching data and surface structure information. The neutral
HF density and F atomic density was measured by FTIR and actinometry based on opticalemission spectroscopy. Figure 1 illustrates the dependence of the SiO2 ER etched at 20 and −60
C on H2 content in the CF4/H2 plasmas. For the samples etched at 20C, the ER decreased
monotonically from 2.6 to 1.3 nm/s as the H2 content was increased from 20 to 70 %, which is
attributed to the well-known scavenging reaction of H atoms with F [2]. Due to the reactions,the concentrations of the main etchants for SiO2, such as F and CFx radicals/ions decrease withincreasing H concentrations, which results in the decrease of ER. On the contrary, when the
SiO2 film was etched at −60 C, the ER increased andreached to the maximum of approximately 3.4 nm/s as H2concentration increased to 33 %. Based on the results of HF
and F atomic density, the trend in ER at −60 C depends on
the HF molecules formed by the plasmas rather than the Fradicals or other etchants like CFx ions. The in situ FTIR
shows that the absorption of H2O and HF molecules on the
SiO2 surface after plasma etching at −60 C. Based on the
results, an etching mechanism, so-called pseudo-wet
plasma etching, based on plasma-assisted reaction between
SiO2, HF and H2O was proposed.
[1] T. Ohiwa et al., Jpn. J. Appl. Phys., 31, 405 (1992).
[2] D. C. Marra, et al., J. Vac. Sci. Tech. A 15, 2508 (1997).

Fig. 1 Dependence of etch rate of
SiO2 etched by CF4/H2 plasma at
Ts = 20 and −60 C.

Feasibility of applying non-thermal plasma to the degradation ofpharmaceuticals in real medical wastewater
Wei-Cheng Lin1, Chih-Yu Ko1, Jang-Hsing Hsieh2 and Wen-Hui Kuan 1*
1

Department of Safety, Health and Environmental Engineering, Ming Chi University of Technology, Taishan,
New Taipei, Taiwan*Corresponding author. whkuan@mail.mcut.edu.tw
2Center for Plasma and Thin Film Technologies, Ming Chi University of Technology, Taishan, New Taipei,
TaiwanDue to the limitations of traditional wastewater treatment processes in effectively degrading

pharmaceuticals and personal care products (PPCPs), these pollutants have been identified to be discharged into
environmental water bodies from urban wastewater treatment. PPCPs not only induce antibiotic resistance inbacteria in natural ecosystems but also have the potential to promote the formation of superbugs. Although theconcentrations of these compounds or their disinfection byproducts in the environment are not high, long-term
exposure may lead to biological mutations.
In this study, a non-thermal plasma system reactor using dielectric barrier discharge (DBD) was
developed for wastewater treatment to degrade various pharmaceuticals present in medical wastewater. The
concentrations of reactive species O3, H2O2, and OH radicals and the degradation of target pollutants (amoxicillin)
were investigated in terms of the reactor layout and the water quality conditions. Real wastewater discharged froma hospital with 1500 beds in north of Taiwan were sampled and subjected into the developed non-plasma reactor.
The results showed that the removal efficiency reached 90% or above at five different frequencies, with energy
efficiency ranging from 0.38 to 0.42 gkW-1h-1, indicating the effectiveness of the module system in amoxicillin
degradation. In the treatment of actual hospital wastewater with the spike of standard samples, the removal
efficiency also reached 82%-93%, demonstrating the feasibility of plasma in actual hospital wastewater treatment.

GN-I-13

Novel plasma source for atomic scale processing
JY Park, MS Kim, and ChinWook Chung
1

Plasma electronics Lab., Dept. of Electrical Engineering, Hanyang University,
222, Wangsimni-ro, Seongdong-gu, Seoul, 04763, Korea
joykang@hanyang.ac.kr

Semiconductor processing has been advancing from the nano to the atomic scale. For
atomic-scale processing, the plasma source need to be precisely controlled to minimize damage,such as UV radiation damage, ion-induced damage, and charge accumulation damage. In thispresentation, we will introduce an Ultra Low Electron Temperature (ULET) plasma (Te < 0.5eV) as a novel plasma source enabling us to perform damage-free plasma processing. We will
also explain how to produce the ULET plasma. It is demonstrated that charge accumulationeven in a patten with high aspect ratio is almost eliminated, and graphene remains undamaged
in the ULET plasma, while it is heavily damaged in conventional plasma processes. The ULET
plasma shows great promise for applications in atomic-scale plasma processing.

GN-I-14

Yttrium-based plasma etching resistant coating obtained by gas flow
sputter deposition
Ping-Yen Hsieh1,2, Tzu-Chun Lin1, Ying-Hung Chen1,2 and Ju-Liang He1,2
1

Department of Materials Science and Engineering, Feng Chia University
No. 100, Wenhwa Road, Seatwen District, Taichung City 40724, Taiwan.
pyhsieh@fcu.edu.tw

Institute of Plasma, Feng Chia University
No. 100, Wenhwa Road, Seatwen District, Taichung City 40724, Taiwan.
2

In the semiconductor plasma etching process, the plasma gas not only reacts with siliconwafers for circuit patterning but also reacts with process equipment, including pipelines, shower
heads, chambers, and all components in contact with plasma. This results in device
contamination , reduced service life of parts, and failure of IC devices, ultimately affecting theetching efficiency, wafer performance, and production yield. Among other plasma etching
resistant materials, yttrium oxide (Y2O3) is a promising material for providing oxygen and/or
fluorocarbon plasma etching resistance. By taking advantage of high plasma density, highthrowing power, and high deposition rate, this study aims to use gas flow sputtering (GFS)
technique to deposit yttrium-based coating, Y2O3, on silicon substrate. The anti-plasma etchingability of the obtained Y2O3 coatings in CH4/O2 mixture was further evaluated.
Experimental results show that, without additional heating, the obtained GFS-Y2O3 coating
possesses a crystalline dense columnar structure with a (111) preferred orientation under anoxygen-rich atmosphere . The deposition rate for GFS-Y2O3 coatings can reach 3.0 μm/h, which
is substantially higher than those many other sputtering processes. Based on the CH4/O2 plasma
etching test results, the GFS prepared Y2O3 coatings exhibit low plasma etching rate than bare
Si wafer, demonstrating their excellent plasma resistance. These results indicate the potentialof the GFS prepared yttrium-based coating as a novel plasma etching resistance material forsurface modification on semiconductor process components.

Posters
October 17（Tuesday）

P-1

Design of a Thomson scattering system for atmospheric plasma sources
Y.-G. Kim1 and S. Park1
1

Institute of Plasma Technology, Korea Institute of Fusion Energy,
Gunsan 54004 Korea
ykim@kfe.re.kr

In the plasma chemistry and biomedical field, reactive oxygen and nitrogen species (RONS),
including oxygen atoms, ozone, hydroxyl radicals, nitric oxide, and nitrogen dioxide, play animportant role because of their high reactivity [1, 2]. Cold atmospheric plasma is known to
produce a wide range of RONS. Numerous techniques, such as corona discharge, dielectricbarrier discharge (DBD), radio-frequency discharge, and microwave discharge, have beendeveloped and explored to generate plasma under atmospheric pressure and room temperature
condition. However, study on the relationship between “plasma parameters” and “radical
generation” is relatively rare possibly due to the difficulty of direct quantification of the plasma
parameters such as velocity distribution function, temperature, or density.
Recently, the Korea Institute of Fusion Energy (KFE) has embarked on the development of
a complex plasma diagnostic system aimed at enabling quantitative research on the productionof radicals and metastable species, along with their relationship with electron kinetics. It will
include spectroscopic systems, including laser-induced fluorescence (LIF), tunable diode laser
absorption spectroscopy (TDLAS), cavity ring-down spectroscopy (CRDS), and Thomson
scattering (TS). Among the various methods, the TS diagnostic system takes precedence as theprimary focus of development, as it is a key diagnostic for plasma measurement.
The TS system is widely recognized as a powerful diagnostic method for measuring theabsolute electron temperature and the density within a given scattering volume [3-6]. However,owing to the extremely small cross section of Thomson scattering (6.65×10-29 m2), the TS
system requires a stable laser source, careful alignment, efficient optical components, andhighly sensitive detectors to ensure accurate measurement. Furthermore, care must be taken onhigh background pressure, low electron temperature, and density. Foremost among theseconcerns is the constraint imposed by air breakdown and multi-photon ionization, which
restricts the maximum permissible laser energy to approximately 20 mJ [7]. For successful
measurement of TS signal with a favorable signal-to-noise ratio, the proposed approach
involves employing an emICCD, a combination of electron multiplier charge-coupled device(emCCD) and image intensifier (I-) while accumulating a number of scattered signals over along period or laser repetition.
[1] A. G. Volkov et al., Journal of the Royal Society Interface, 16, 20180713 (2019).
[2] D. B. Graves and G. Bauer, Key Roles of Reactive Oxygen and Nitrogen Species. In: H.-R.
Metelmann, et al. (eds) Comprehensive Clinical Plasma Medicine, Springer, Cham, 11 Jan 2018.
[3] M. J. van de Sande, Laser scattering on low temperature plasmas: high resolution and straylight rejection, PhD Thesis, Eindhoven University of Technology (2002)[4] H. Yoshida et al., Japanese Journal of Applied Physics, 42, 439 (2003)[5] J. H. Lee et al., Review of Scientific Instruments, 81, 10D528 (2010)[6] A. F. H. van Gessel et al., Plasma Sources Science and Technology, 21, 015003 (2012)[7] Y. Sonoda et al., The Japan Society of Plasma Science and Nuclear Fusion Research, 8, 696(2009).

P-2

Irradiation experiment of new type of divertor heat removal component
fabricated by AMSB to LHD divertor plasma
Masayuki Tokitani1, Yukinori Hamaji1, Yutaka Hiraoka2, Yuki Hayashi1, Suguru Masuzaki1,
Hiroyuki Noto1, Tatsuya Tsuneyoshi3, Yoshiyuki Tsuji3, Gen Motojima1, Hiromi Hayashi1,
Takanori Murase1, Takeo Muroga1 and Tomohiro Morisaki1
1

National Institute for Fusion Science, Toki, Gifu 509-5292, Japan
2
Okayama University of Science, Okayama 700-0005, Japan
3
Nagoya University, Furo-cho, Chikusa, Nagoya 464-8603, JapanThe novel method “Advanced Multi-Step Brazing (AMSB)” has been developed tofabricate a new type divertor heat removal component in the National Institute for Fusion
Science (NIFS), in which the fabricated new component showed an excellent heat removal
capability with ∼30 MW/m2. As a next step, the component was exposed to repetitive heatloading in the Large Helical Device (LHD) to demonstrate a dulability in the large sized plasma
confinement device.
The principle of the AMSB is a repetitive application of the advanced brazing technique(ABT). The ABT was originally developed to braze tungsten (W) to ODS-Cu (GlidCop®) with
the BNi-6 (Ni-11%P) filler material, in our previous work [1]. Later we develped the leaktightness joint procedures of GlidCop® (GlidCop®/GlidCop®), and stainless steel (SUS) and
GlidCop® (SUS/ GlidCop®) accompanied with high enough joint strength to be comparablewith bulk GlidCop®. One of the special feature of in the ABT joints of GlidCop®/GlidCop® andthe SUS/GlidCop® is strong trelance against the repetitive brazing heat-cycle, i.e., the repetitive
application of the ABT can be applied for fabricating a single heat removal component.
“New type of divertor heat removal component“ with the rectangle-shaped fluid flow pathand the V-shaped staggered rib structure were successfully produced by the AMSB; therein apre-processed rectangle-shaped cooling flow path channel was sealed with a GlidCop® and SUS
lid structure with leak-tight conditions. the new component was installed in the divertor strike
position of the Large Helical Device (LHD) as shown in Fig. 1, and exposed to neutral beam
injection–heated plasma discharges with 1180 shots (~8000 s) in total. After the exposure,several microstructural analyses were conducted by using a dual-beam type of focused-ion
beam/scanning electron microscopy (FIB-SEM) device on the W armor plate.
An extremely high heat removal
response in the component wasdemonstrated through the quick increase
and decrease of the temperature of the W
plate located on the divertor strike point
during discharges. Though submillimeterscale damages, such as unipolar arc trails
and microscale cracks, were identified on
the W surface, such a high heat removal Fig. 1 Schematic figure for an exposure experiment of new
response did not show any sign of type of divertor heat removal component to a LHD divertor
degradation during the 1180 shots (~8000 plasma. The component was installed in the divertor leg
position in the LHD and exposed to plasma discharges withs) of plasma discharges.
1180 shots (~8000 s) in total.

[1] M. Tokitani et al., Nucl. Fusion 57 (2017) 076009.

P-3

Theoretical issue of the electron cyclotron emission
with decay process in a waveguide
Yuki Goto1 and Tomio Petrosky2,3
National Institute for Fusion Science, National Institute of Natural Sciences
322-6, Oroshi-cho, Toki 509-5292, Japan
goto.yuki@nifs.ac.jp

1

Center for Complex Quantum Systems, The University of Texas at Austin,
2515 Speedway, Stop C1609, Austin 78705, USA

2

Institute of Industrial Science, The University of Tokyo,
5-1-5, Kashiwanoha, Kashiwa 277-8574, Japan

3

Electron cyclotron motion and its emission are observed in various places such as the
Earth’s magnetosphere represented by auroras, neutron stars in space, free electrons within
metals, and magnetic confinement fusion plasmas, and are playing a crucial role inastrophysics, condensed matter physics, and fusion science. As is well known, cyclotron
motion is a typical example of the classical radiation damping. And phenomenological
Lorentz-Abraham (LA) equation has established in classical mechanics to deal with thisphenomenon of radiation damping in classical mechanics. However, this classical radiation
damping has not been solved yet. Because the LA equation includes a third-order time
derivative term of the electron’s position in the equation of motion, which causes difficultyin finding a physically meaningful solution.
Thus, we treat this issue by using classical Friedrichs model without perturbation
analysis. The Hamiltonian known as the Friedrichs model in quantum mechanics reveals
that the phenomenon of decay of a harmonic oscillator while emitting photons can be derived as an exact solution of the Heisenberg equation in Fock space [1]. In our approach, by“classicalization” the conclusions of Friedrichs’s quantum theory, we analyzed the electron
cyclotron emission by using classical Friedrichs model in waveguide [2]. In this talk, wewill present the essence of classical radiation dumping problem and show how to solve thedifficulty for deriving a decay solution with mathematically consistently that violates thetime symmetry from the fundamental equations of physics that originally has timesymmetry.
[1] K. Friedrichs, Commun. Pure Appl. Math., 1, 361 (1948).
[2] T. Petrosky, C. O. Ting, and S. Garmon, Phys. Rev. Lett., 94, 043601 (2005).

P-4

Simulation analysis of lithium transport in the peripheral plasma during
impurity powder injection in the Large Helical Device
Mamoru Shoji1,2, Gakushi Kawamura1,2, Tomoko Kawate1,2, Suguru Masuzaki1,2, Naoko
Ashikawa1,2, Robert Lunsford3, Erik P. Gilson3, Federico Nespoli3, and Novimir Pablant3
1

National Institutes of Natural Sciences, National Institute for Fusion Science322-6 Oroshi-cho, Toki, Gifu 509-5292, Japan
shohji.mamoru@nifs.ac.jp
2
The Graduate University for Advanced Studies, SOKENDAI, Shonan Village, Hayama, Kanagawa 240-0193,
Japan
3
Princeton Plasma Physics Laboratory, 100 Stellarator Road, NJ 08540, United States of America

Multi-species impurity powder dropper (IPD) [1] has contributed to the improvement of theion energy confinement in the plasma in the Large Helical Device (LHD) [2]. As anotherpromising usage of the IPD, lithium coating on the surface of the in-vessel components wastried by lithium powder injection in the last experimental campaign for the first time. The
purpose of the lithium coating was to reduce the recycled particles on the plasma-facing
components and to sustain them during long plasma discharges. A stereoscopic fast-framing
camera has been installed in an upper port close to the IPD for monitoring the trajectories ofdropped lithium powders and the ablation positions in the peripheral plasma. Figure 1 shows
an image of the ablation of a dropped lithium powder (850 m in diameter) observed with thecamera. It indicates an oblique bright line along a magnetic field line, which is initiated fromthe ablation position of the lithium powder. The change of the ablation positions toward theoutboard side of the torus was observed with the increase in the plasma density.
The analysis of the lithium powder trajectories in the peripheral plasma was performed
using a three-dimensional edge plasma simulation code (EMC3-EIRENE) [3] coupled with adust transport simulation code (DUSTT)[4, 5] in a full-torus model for LHD [6].
It has successfully reproduced the changeof the ablation position of the lithium
powder by the deflection of the
trajectories due to the effect of the plasma
flow in an upper divertor leg. The
simulation also calculates the threedimensional density profile of lithium
ions in the peripheal plasma, providing theline-integrated intensity profiles oflithium-ion emission along the line ofsight of spectrometers. In the forum, thelithium-ion transport in the plasma is Fig. 1: An image of the ablation of a lithium
investigated by comparing the simulations powder injected by the IPD for a high plasma
with the spectroscopic observations.
density (𝑛 ~6×1019 m-3).
[1] A. Nagy et al., Rev. Sci. Instrum., 89, 10K121 (2018).
[2] F. Nespoli et al., Nat. Phys., 18, 350 (2022).
[3] Y. Feng et al., Plasma Phys. Control. Fusion, 44, 611 (2002).
[4] A. Y. Pigarov et al., Physics of Plasmas, 12, 122508 (2005).
[5] R. Smirnov et al., Plasma Phys. Control Fusion 49, 347 (2007).
[6] M. Shoji et al., Contrib. Plasma Phys., 60, e201900101 (2020).

P-5

Molecular Dynamics Simulation for
Elucidation of Vacancy Coalescence in Tungsten Crystal
Sotaro Tsuru1, Hiroaki Nakamura1,2, Yuki Goto2, Miyuki Yajima2,
Seiki Saito3, and Shunsuke Usami2
1

School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japantsuru.sohtaro@nifs.ac.jp
2
National Institute for Fusion Science, National Institute of Natural Sciences 322-6, Oroshi-cho, Toki 509-5292,
Japan
3
Graduate School of Science and Engineering, Yamagata University, 4-3-16, Jonan, Yonezawa, 992-8510,
Japan

In a fusion reactor environment, tungsten, which
is used as the plasma-facing material, is irradiatedwith neutrons and high-energy hydrogen isotopes
that result from the D-T fusion reaction. This
irradiation leads to the formation of defects known asvacancies in the tungsten. In the previous research
conducted by Yajima et al., phenomenon of vacancy
coalescence was discovered experimentally [1]. The
report indicates that vacancies tend to coalesce more
readily when hydrogen atoms are contained in thevacancies compared to when they are not. In order tounderstand the atomic-level effect of hydrogen atoms
on vacancy coalescence, we analyzed the behavior of
vacancies formed in tungsten using the molecular
dynamics simulation by LAMMPS [2].
Fig. 1: Arrangement of vacancies
As a first attempt of understanding the vacancy
in tungsten crystal
behavior, the case in which a single vacancy exists ina tungsten crystal was conducted [3]. In this study, we set two vacancies in a tungsten crystal
and analyze the interaction between the vacancies in detail. Figure 1 shows the simulation
model. In order to elucidate the effect of hydrogen contained in the vacancies on the interaction
between the vacancies, simulations are performed with different numbers of hydrogen invacancies. As the interaction potential between tungsten and hydrogen, we use 2014-Bonny-GGrigorev-P-Terentyev-D--W-H-He-EAM1 [4]. Our simulations show that the tungsten atoms
between the vacancies migrate, and the two vacancies coalesce to form a single large vacancy.
In this presentation, we will discuss the results of our simulations in detail.
Acknowledgment:
The computation was performed using Research Center for
Computational Science, Okazaki, Japan (Project: 22-IMS-C104) and Plasma Simulator of NIFS.
The research was supported by Japan Society for the Promotion of Science (Grant Nos.
JP19K14692, JP22H05131, JP23H04609, JP22K18272, JP23K03362), by the NINS programof Promoting Research by Networking among Institutions, by the NIFS Collaborative Research
Programs (NIFS22KIIP003, NIFS22KIGS002, NIFS22KISS021) and by the ExCELLS Special
Collaboration Program of Exploratory Research Center on Life and Living Systems.
[1] M. Yajima et al., Phys. Scr., 96, 4042 (2021).
[2] Aidan P. Thompson et al., Comp. Phys. Comm., 271, 108171 (2022)[3] H. Nakamura et al., J. Adv. Simul. Sci. Eng., 10, 132(2023).
[4] G. Bonny et al., J. Phys. Condens. Matter, 26(48), 485001(2014).

P-6

Nanopatterning of Si by low-energy He plasma irradiation
Zhe Liu1, Long Li1, Zeshi Gao1, Ze Chen1, Chao Yin1, Shifeng Mao1, Shin Kajita2, Noriyasu
Ohno3, Minyou Ye1,*
School of Nuclear Sciences and Technology, University of Science and Technology of China, Hefei, Anhui
230026, People’s Republic of China*e-mail: yemy@ustc.edu.cn
2Graduate School of Frontier Sciences, The University of Tokyo, Chiba 277-8561, Japan
3Graduate School of Engineering, Nagoya University, Nagoya 464-8603, Japan1

The phenomenon of self-organized nanopatterning on material surfaces, particularly Si,
through ion beam irradiation (IBI) has garnered considerable attention in recent decades.
Significantly noteworthy progress has been made in elucidating the underlying mechanisms
governing ion-material interactions, coupled with notable advancements in experimental
results. These outcomes affirm the versatility, expeditiousness, and cost-effectiveness of the
IBI method as a bottom-up approach for achieving surface nanopatterning. This technique
exhibits promising potential for applications across various domains [1,2].
However, a legitimate constraint emerges concerning the ion-substrate pairing:
scenarios arise where no structures manifest when the ion possesses a lower mass than thesubstrate [3]. This phenomenon substantiates the inadequacy of He and Ne ion beams for Si
nanopatterning, contributing to the limited extent of related investigations. Nevertheless, awell-established realization within the past decade reveals that low-energy He plasma
irradiation can induce various nanostructure formations on diverse metals andsemiconductors [4]. This finding contradicts preceding knowledge, presenting a paradox.
In this study, we experimentally investigate Si substrates exposed to low-energy (< 100eV) and high-flux (~ 1022 m-2s-1) He plasma irradiation under normal incidence. Byrigorously maintaining contamination control measures, the irradiated Si surface reveals
distinctive mountain-like nanostructures with well-defined facets and grooves extending
along mutually perpendicular <110> directions. In cases involving pre-deposited metal
impurities, notably Ta, which previously exhibited no impact on nanostructure growthduring Ar ion beam irradiation trials, a densely packed arrangement of nanocones emerges
on the irradiated Si surface. SEM cross-sectional images distinctly illustrate the presence ofHe bubbles, oriented nearly perpendicular to the irradiated surface. These subsurface He
bubbles introduce a novel instability, fostering nanostructure formation on the Si surface,even under normal incidence conditions. This finding necessitates a reassessment of thenanopatterning effects of low-energy He ion irradiation on materials. Furthermore, it calls
for a comprehensive investigation into the influence exerted by He bubble formation on
the established BH theory and the CV effect in surface evolution.
[1] S. A. Norris, Appl. Phys. Rev., 6, 1 (2019).
[2] L. Vázquez, J. Phys. Condens. Matter, 34, 33 (2022).
[3] B. Rauschenbach, Low-Energy Ion Irradiation of Materials (Springer Nature, 2022).
[4] S. Kajita, J. Appl. Phys., 132,18 (2022)..

P-7

Growth of micro-pillars on tungsten by helium plasma exposure
with impurity gases
Rongshi Zhang1, Shin Kajita2, Hirohiko Tanaka3, Yuta Yamamoto3 and Noriyasu Ohno1
1

2

3

Graduate School of Engineering, Nagoya University
Furo, Chikusa, Nagoya 464-8603, Japanzhang.rongshi.r1@s.mail.nagoya-u.ac.jp

Graduate School of Frontier Sciences, The University of Tokyo, Japan,
5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8561, Japan

Institute of Materials and Systems for Sustainability, Nagoya University,
Furo, Chikusa, Nagoya 464-8603, Japan

Plasma-material interactions have been noticed and investigated for a long time. Theinteraction between helium (He) and tungsten (W) leads to many morphological changes on W,
and one of the most well-known morphology changes is the fuzzy nanostructure [1]. In recently
years, a cone-like structure called nanotendril bundles (NTB) was found to be formed on W by
He plasma exposure with additional impurity gases such as neon (Ne), nitrogen (N2) and argon(Ar) [2]. Both of the fuzz and NTB enhance the field emission of W, which leads to a possibilityof arcing and enhancement of erosion on the divertor plate [3, 4]. Thus, the morphology changes
occurring on W are a concern for the fusion reactor.
In this research, W plates were exposed by He plasma with Ne, N2, or Ar in linear plasma
device NAGDIS-II. The incident ion energy was controlled to be 150 – 200 eV and the partial
gas pressure of impurity gas was in a range of 3% - 20%. During the plasma exposure, thesurface temperature of the sample was kept to be ~ 1550 K, which was measured by an infrared
pyrometer (~1.6 μm).
After the plasma exposure, the morphological change of W surface was confirmed byscanning electron microscopy (SEM). When N2 impurity was added, a micro-sized pillar-likestructure was formed on W with a height of several μm as shown in Fig. 1. When the Ar
impurity gas was added, the pillars grown higher to several tens μm. Thus, the type of impurity
gas affects the growth of micro-pillars.
The field emission property of micro-pillars was measured in a vacuum chamber. For the
sample exposed by He-N2 mixed plasma, the field emission current from the sample was lower
than 1 μA at 2000 V/mm. On the other hand, for the sample exposed by He-Ar mixed plasma,
the field emission current became ~ 100 μA at ~ 2500 V/mm, which is a similar value to thatof NTBs [5]. It should be investigated whether these micro-pillars can trigger an arcing in a
nuclear fusion reactor.
[1] S. Takamura et al., Plamsa Fusion Res. 1, 051 (2006).
[2] D. Hwangbo et al., Nucl. Fusion 58, 096022 (2018).
[3] D. Sinelnikov et al., IEEE Trans. Plasma Sci. 47,
5186-5190 (2019).
[4] R. Zhang et al., Plasma Fusion Res. 16, 2405069(2021).
[5] R. Zhang et al., Mater. Res. Express 10, 054002(2023).

Fig. 1: SEM micrograph of
micro-pillars
which
were
formed by He-N2 mixed plasma

P-8

Surface modification of ZrC dispersion-strengthened W
under low energy He plasma irradiation
Long Li1, Zhe Liu1, Ze Chen1, Chao Yin1, Shifeng Mao1, Xuebang Wu2,
Noriyasu Ohno3, Minyou Ye1,*
1

School of Nuclear Sciences and Technology, University of Science and Technology of China,
Hefei, Anhui 230026, People’s Republic of China
2

Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences,
Hefei, Anhui 230031, People’s Republic of China
3

Graduate School of Engineering, Nagoya University, Nagoya 464-8603, Japan*e-mail: yemy@ustc.edu.cn

Tungsten (W) is considered as a candidate for plasma-facing materials (PFMs) in fusion
devices. However, the brittleness, poor machinability, and low strength at high temperature
limit its performance. To resolve these problems, various W with enhanced mechanicalproperties have been developed over recent decades. ZrC dispersion-strengthened W exhibitshigh strength/ductility, low ductile-to-brittle transition temperature, and excellent thermal
shock resistance, making it a promising candidate PFM for future fusion devices [1]. A recent
study of irradiation effect on W-0.5 wt% ZrC using low energy He plasma will be presented.
The W-0.5 wt% ZrC plates were exposed to He plasm with low energy (< 100 eV) at
different irradiation fluences up to (6 × 1024-2 × 1026 He∙m-2) in CLIPS (Compact LInear
Plasma-Surface interaction device). At 1190 K, the typical fuzz nanostructures were observedon the W matrix. Moreover, the fuzz showed comparable thickness and structure features ofpure W, which suggested that the addition of particles did not affect its resistance to high fluence
He irradiation at high temperature. While, the sputtering process dominated the behavior ofparticles. Under 6 × 1024 He∙m-2, only nanopores appeared on the sub-surface. With the fluenceincreasing to 5 × 1025 He∙m-2, the surface was relatively uneven and further eroded, forming
larger holes and stalagmitic structures. W was enriched on the top of stalagmitic structures, due
to the subthreshold sputtering under He irradiation. With the fluence increasing to 2 × 1026 He∙m-2, the particles disappeared. In addition, near the W-particle interface, unique layered
nanotendrils formed. The inner W-riched skeleton and outer Zr-riched layer indicated that thelayered nanotendrils might result from fuzz extension combined with particles sputtering andredeposition. The detail results will be presented in this conference.
[1] Xie, Z.M., et al., Extraordinary high ductility/strength of the interface designed bulk W-ZrC
alloy plate at relatively low temperature. Sci Rep, 2015. 5: p. 16014.

P-9

Probabilistic modeling of impurity transport based on
the drift-kinetic equation
Ryutaro Kanno1,2, Gakushi Kawamura1,2, Seikichi Matsuoka1,2,
Masanori Nunami1,3 and Shinsuke Satake1,2
12

National Institute for Fusion Science, Toki 509-5292, Japan
kanno@nifs.ac.jp

The Graduate University for Advanced Studies, SOKENDAI, Toki 509-5292, Japan
3
Nagoya University, Nagoya 464-8601, JapanWe are developing a probabilistic model of collisional transport of a heavy impurity like tungsten in
the edge of a quasi-steady three-dimensional fusion plasma, based on the drift-kinetic equation [1]. Here,the impurity is assumed to be sufficiently rarefied, i.e., its number density is 10-4–10-5 or more times
smaller than the number density of the background plasma, and to contribute little to self-consistentelectromagnetic field. In such a case, when electromagnetic fluctuation is generated by, for example,
turbulence of the background plasma, the distribution function of the impurity is also assumed to befluctuating. The computational cost of a kinetic simulation of the impurity transport including such an
electromagnetic fluctuation is estimated to be high. Considering that the behavior of the distributionfunction of the impurity is probabilistic, it is helpful for reducing the cost that effect of theelectromagnetic fluctuation is modelized as a noise having finite amplitude in the impurity transport.
Here, the noise is assumed to have zero expectation and is bounded.
It is known that when considering the distribution function of the impurity only in the velocity space,such a probabilistic fluctuation does not change the distribution. This fact is mathematically guaranteed,as shown in Theorem 8.4.3 in [2]. On the other hand, when effect of the probabilistic fluctuation isconsidered in the drift-kinetic equation of the impurity, role of the effect has not been explained.
Therefore, we first investigate effect of such a noise in the drift-kinetic equation by using a drift-kinetic
simulation code, KEATS [1]. When the noise affects the impurity only in the velocity space, we findthat the effect is negligible in the drift-kinetic equation, as shown in the figure below, although the noise
influences orbits of the impurity
particles in the configuration space
through the velocities changed. We seethat the radial particle flux of the
impurity is determined by the friction
and thermal forces with the backgroundions, which is the same result in [1].
On the other hand, when the noise
affects the distribution function in the 5dimensional phase space, the effectbecomes complicated. We consider thetime-evolution of an ensembleaveraged distribution function of the
impurity for understanding how the
distribution function becomes quasisteady. The modeling shows that thenoise effect can be ignored in the driftkinetic equation of the ensembleaveraged distribution function.

[1] R. Kanno et al., Nuclear Fusion 60 (2020) 016033.
[2] B. Øksendal, Stochastic Differential Equations (Springer-Verlag, 2003).

P-10

2-D spectroscopic measurement of Balmer series in detached plasma
with ICR heating
Naonori Okada1, Ryuichi Ohonuma1, Akira Tonegawa1 and Kohnosuke Sato2
1
Tokai University,
4-1-1, Kitakaname, Hiratuka-shi, Kanagawa 259-1292, Japan
8BSP1107@gmail.com
2

Reserch Institute for Applied Mechanics, Kyusyu University
7-4-4, Motooka, Nishi-Ku, Fukuoka-shi, Fukuoka,JapanThe divertor is subject to damage by high heat flow particles emitted from the core plasma.
Therefore, it is considered to reduce the heat load on the divertor plates by introducing neutral
gas to generate a detached plasma. In the divertor of future DEMO-class devices, further
reduction of the heat load is required, and simulation experiments of advanced divertors
employing a divergent magnetic field configuration, such as the Super X divertor, are in
progress. Therefore, basic research on heat load reduction in detached plasma is being actively
conducted in small linear divertor simulators.
However, the ion temperature of the plasma produced by most linear divertors is as low as
about 3 eV, which is significantly different from the ion temperature of the divertor plasma oflarge devices such as the International Thermonuclear Experimental Reactor (ITER), which is
10-20 eV. Therefore, the effect of ion temperature on detached plasma generation has been an
open question in basic research using linear divertor simulators. In addition, the process ofdetached plasma generation in the divergent field configuration used in advanced divertors has
also been mainly studied by simulation, and few basic experiments have been conducted.
The objective of this study is to investigate the generation process of detached plasma withrespect to ion temperature by ion cyclotron resonance (ICR) heating of high-density sheet
plasma generated in a linear divertor simulator (TPDsheet-U) [1].
In this study, we investigated the process of detached plasma formation when the ion
temperature is varied by ICR heating in a high-density sheet plasma generated in a divertorsimulator TPDsheet-U. The plasma is heated by ICR, and the ion temperature is varied. The
plasma thermal energy was measured with a diamagnetic coil, the electron temperature anddensity with a Langmuir probe, and the two-dimensional emission intensity distribution of Hα,
Hβ, and Hγ with a high-speed camera equipped with an Arbaa prism spectrometer. The results
show for the first time that increasing the ICR heating power decreases Hγ and suppresses theformation of exfoliation plasma.
Reference[1] Okada Naonori, et al. Fusion
Engineering and Design 192 (2023)
113596.

Fig1. Characteristics of 2-D spectroscopy of Balmer series(Hα, Hβ, and Hγ) in detached plasmas with increasing
ICR heating power at gas pressure of 0.8 Pa.

P-11

Analysis of Molecular Activated Recombination in Hydrogen Plasma
Produced in Radio-Frequency Plasma Source DT-ALPHA
Keigo Yoshimura1, Hiroyuki Takahashi1, Tomohiro Seino1, Ryota Nishimura1,
Akihiro Kanno1, Yusaku Takahashi1, Tomoya Hara1, Shigetaka Kagaya1,
Akinobu Matsuyama2, Tetsutarou Oishi1 and Kenji Tobita1
1

Department of Quantum Science and Energy Engineering, Tohoku University,
6-6-01-2 Aoba, Aramaki, Aoba, Sendai, Miyagi 980-8579, Japankeigo.yoshimura.s5@dc.tohoku.ac.jp
2

Graduate School of Energy Science, Kyoto University,
Uji 611-0011, JapanOne of the key challenges for future fusion reactors is safe control of power exhaust fromburning core plasma to divetor plates. A promising way to control the power exhaust is theformation of detached divertor, which is facilitated by electron-ion recombination (EIR) andmolecular activated recombination (MAR). DA-MAR (Dissociative Attachment-MAR) andIC-MAR (Ion Conversion-MAR) are known to be main reaction chains of MAR. Comparedwith DA-MAR, publications on IC-MAR have been quite limited because of a difficulty inobtaining evidence of the IC-MAR. For this situation, it is of great significance of to establish
a methodology to experimentally distinguish the IC-MAR reaction. In our group, we have been
conducting divertor plasma simulating experiment on hydrogen MAR using a radio-frequency
plasma source DT-ALPHA. Although we have achieved to obtain the experimental results thatindicate strong enhancement of MAR [1], DA-MAR and IC-MAR were not distingished yet.
In this paper, we present efforts to explore the methodology to experimentally distinguish the
IC-MAR reaction based on experimental results of hydrogen plasma obtained in the DTALPHA.
The DT-ALPHA is approximately 2 m in length and plasma is produced by 13.56 MHz
radio-frequency (RF) discharge. Hydrogen working gas is supplied at the upstream end of thedevice. Secondary hydrogen gas is supplied at the downstream region to enhance MAR. The
hydrogen neutral pressure at the secondary gas feeding region was controlled up to 3.6 Pa by
increasing the amount of the secondary gas. To maintain the discharge condition during theexperiment, the upstream neutral pressure was kept almost constant by adjusting the feeding
rate of the working and secondary gases. Langmuir probes, spectrometers and a retarding field
analyzer (RFA) were used for the measurement.
The electron temperature at the secondary gas feeding region decreased monotonically from
17 eV to 6 eV with increasing the neutral pressure. In the experiment, a rollover of the electron
density was clearly observed, showing a sign of enhancement of the plasma recombination. The
observed Balmer line intensity ratio (H/H), which is a good indicator of DA-MAR, wasalmost independent of the neutral pressure. Numerical analysis with a collisional-radiativemodel indicated that the density rollover was dominated by the IC-MAR reaction. To confirm
the results, we plan to measure the hydrogen ion temperature and evaluate the reaction rate ofion conversion. The result of the additional measurement will be presented, as well.
This work was supported by JSPS KAKENHI Grant Numbers JP20H01883 andJP22K18699 and JST Grant Number JPMJFS2102.
[1] K. Yoshimura et al., Plasma Fusion Res. 17, 1201082 (2022).

P-12

Diffusion Behavior of Adatom on Tungsten Surface
Evaluated by Density Functional Theory Calculation
Arimichi Takayama1,2 and Atsushi M. Ito1,2
1

National Institute for Fusion Science, National Institutes of Natural Sciences,322-6 Oroshi-cho, Toki, Gifu 509-5292, Japan
Takayama.arimichi@nifs.ac.jp
2

Graduate Institute for Advanced Studies, SOKENDAI,
322-6 Oroshi-cho, Toki, Gifu 509-5292, JapanThe authors are interested in tungsten nano structure (so called fuzz), which is formed dueto helium irradiation with relatively low incident energy (less than about 100 eV) and was firstly
reported by Prof. Takamura in 2006 [1]. Its formation mechanism is not clear and is believedto involve multiple elementary processes. Motion of adatom which is trapped on a surface isregarded as one of these processes. In the present work, migration energy of adatom on tungsten
surface [2], which is related to surface diffusion is evaluated by ab initio calculations based on
density functional theory (DFT), and plausible diffusion path is revealed.
The used method is the followings: a target system having supercell of 3x3x6 unit lattice
tungsten (BCC) with an adatom on (0 0 1) surface is prepared. Surface is introduced by vacuum
region with the size of 6 unit cells in z-direction and fixed atoms in the bottom two layers of thesystem. Periodic boundary condition in (x-, y-, z-) directions are imposed. Brillouin zone
sampling (k-points) is 4x4x1 and the SCF convergence criterion is 1.0x107 hartree. Nudged
elastic band (NEB) method with 7 images is used for minimum energy path search. DFT
calculations are performed by the modified version of OpenMX code which is vectorized andtuned for NEC SX Aurora TSUBASA [3-5].
The evaluated migration energy of the case where tungsten adatom does not jump to theadjoining trapping site but moves onto the lattice point on the surface and the surface atom popsout on the surface is 2.03 eV. On the other hand, the one for the case where the adatom jumps
to the adjoining trapping site is 2.85 eV. The similar tendency is obtained for adatom ofmolybdenum, tantalum, and rhenium. In addition, tungsten with adatom of Ta/Mo is 0.43eVless stable / 0.18 eV more stable than the state where the adatom of Ta/Mo and single W atom
are exchanged, respectively. These results imply that it is preferrable that an adatom moves
onto the lattice point on the surface and the surface atom pops out on the surface, and tantalum
adatom prefers to merge into tungsten material.
[1] S. Takamura, N. Ohno, D. Nishijima, and S. Kajita, Plasma Fusion Res., 1, 051 (2006).
[2] Z. Chen and N. Ghoniem, Phys. Rev. B 88, 035415 (2013).
[3] T. Ozaki and contributors, https://openmx-square.org/[4] A. M. Ito, A. Takayama, O. Watanabe, V. Singh, S. Tyagi, and S. S. Singh, Plasma FusionRes., 15, 1203085 (2020).
[5] A. M. Ito, https://github.com/atsushi-m-ito/openmx-vector-patch
This work is partly supported by KAKENHI (19H01882 and 19K21870). Calculations are carried out on"Plasma Simulator Raijin" (NEC SX Aurora TSUBASA) of NIFS with the support and under the auspicesof the NIFS Collaboration Research program (NIFS20KNSS130, NIFS21KNSS156, and NIFS22KISS027).

P-13

Weighted Sum Estimation of Radiation Power andToroidal Asymmetry in LHD
Gakushi Kawamura1,2, Kiyofumi Mukai1,2, Byron Peterson1,2
National Institute for Fusion Science, Toki Gifu 509-5292, JapanThe Graduate University for Advanced Studies, SOKENDAI, Toki Gifu 509-5292, Japan1

2

kawamura.gakushi@nifs.ac.jp

Impurity species act as a radiator in a plasma and affect the plasma transport properties.
Especially heavy impurities such as tungsten are quite important for the fusion plasma design
because of their strong core radiation. In Large Helical Device (LHD), the total radiation power[1] has been estimated as a linear combination of bolometer powers at different toroidal
positions by using a regression analysis of the synthetic data simulating the bolometer
diagnostics with the aid of the numerical transport code EMC3-EIRENE [2]. The feasibility ofthe simple regression analysis of the synthetic dataset has been proved by introducing some
artificial variations to the dataset such as noise, toroidal modulation, and core radiation, which
are not involved in the EMC3-EIRENE model. Evaluation of toroidal asymmetry, or locality,
was also realized by comparison between the estimations with all the bolometers and with abolometer at a certain toroidal position [3].
In this study, the data dataset of the synthetic bolometer diagnostics was updated to include
different magnetic field configurations to cover most of the LHD discharges (see Fig. 1): themagnetic axis position Rax = 3.75 m and 3.9 m in addition to Rax = 3.6 m in the previous study[1]. The influence of each artificial variation type was evaluated, and it was found that all ofthem contribute to the stability of the regression results, and especially the noise component isimportant. Tikhonov regularization was newly introduced for further stability.
In order to realize a quantitative evaluation of toroidal asymmetry, Fourier components wereintroduced as the toroidal variation. The coefficient of each Fourier component was obtainedby the regression analysis for it (see Fig. 2). Time development of the degree of asymmetry andits direction becomes available during a discharge.

Fig. 1: the coefficients for the bolometerchannels in three magnetic configurations.
The four groups separated by the vertical lines
correspond to the four bolometer systems.

Fig. 2: comparison between the estimation andthe input coefficient for the cosine component.
A clear correlation was obtained. The green
line denotes the perfect match.

[1] P. L. Van De Giessen et al., Rev. Sci. Instrum., 92, 033518 (2021).
[2] G. Kawamura et al., Plasma Phys. Contr. Fusion, 60, 3403034 (2018).
[3] B. J. Peterson et al., Nucl. Mater. Energy, 26, 100848 (2021).

P-14

Evaluation of proton density ratio in a bucket-type ion source based on
kinetic code plasma simulation and rate equation for hydrogen ions
Hiroyuki Takahashi1, Ryota Nishimura1, Tomohiro Seino1, Keigo Yoshimura1,
Akihiro Kanno1, Tomoya Hara1, Yusaku Takahashi1, Tetsutarou Oishi1,
Akinobu Matsuyama2, Kenji Tobita1, Kazuo Hoshino3
1Department of Quantum Science and energy Engineering, Tohoku University
Aobayama, Sendai 980-8579, Japanhiroyuki.takahashi.c6@tohoku.ac.jp
2

Graduate School of Energy Science, Kyoto University
Uji 611-0011, Japan

3
Faculty of Science and Technology, Keio University
3-14-1 Hiyoshi, Kohoku-ku Yokohama, Kanagawa, 223-8522, Japan

Future fusion reactors will be operated with detached divertor regime to allow the divertor
plates to withstand large plasma heat load. The detached divertor is facilitated by plasma
volumetric recombination. Although many toroidal plasma devices and linear divertor plasma
simulators demonstrated its capability of the divertor protection, transient behavior of thedetached divertor, which is triggered by energetic ion inflow attributed to the edge-localized
modes (ELMs), has not yet been understood clearly. We have been conducting
ELM-simulating experiments using a radio-frequency plasma source and an ion beam
generator. It was found that ELM-simulating helium ion beam decreases reaction rate of thevolumetric recombination of helium ions [1]. With respect to hydrogen plasma, recently wesucceeded to obtain the experimental results that indicate strong enhancement of hydrogenmolecular activated recombination (MAR) [2]. This achievement enables us to conduct
similar experiments with hydrogen MAR plasma and hydrogen ion beam (H+ beam).
However, one difficulty in use of intense H+ beam is that installation of a mass filter isnecessary to separate ion species, making decrease of ion beam intensity inevitable. Intensityof H+ beam depends on H+ density ratio inside the ion source. Therefore, this study aims tofind suitable operation window to obtain high H+ ratio.
The ion beam source utilized in our device has approximately 80 mm diameter and 90 mm
length. Permanent magnets aligned azimuthally produce multi-cusp magnetic field. Plasma is
produced with the direct-current arc discharge between its body and hot cathode of tungsten
filaments. Ratio of the protons to hydrogen molecular ions in a multi-cusp type ion source canbe calculated with its geometry and plasma parameters inside [3]. However, our ion source is
not equipped with measurement port. Therefore, we use KEIO-MARC kinetic code [4], which
is able to calculate electron temperature and electron density inside a given-size ion source,
using neutral pressure and arc power as input parameters. Combination of this analysis andrate equations for hydrogen ions enables to explore suitable operation window for producing
intense H+ beam. In this presentation, we will report results of these analyses.
This work is supported by the Japan Society for the Promotion of Science JSPS
KAKENHI (Grant Nos. JP20H01883 and JP22K18699).
[1] H. Takahashi et al., Physics of Plasmas 23, 112510 (2016).
[2] K. Yoshimura et al. Plasma Fusion Res. 17, 1201082 (2022).,[3] Y. Okumura et al., Rev. Sci. Instrum. 55, 1 (1984).
[4] I. Fujino et al., Rev. Sci. Instrum. 79, 02A510 (2008).

P-15

Formation of fiber-form nanostructures and He bubbles/holes on tungsten
surfaces by collisional helium arc plasma irradiation
Mitsuo Tajima1, Yusuke Kikuchi1, Tatsuya Aota1, Shiro Maenaka2,
Kazunori Fujita2, Shuichi Takamura2
1

University of Hyogo
2167 Shosha, Himeji, Hyogo 671-2201, Japaner22v011@guh.u-hyogo.ac.jp
2

Yumex Inc.
400 Itoda, Yumesakichou, Himeji, Hyogo 671-2114, Japan

Recently, it has been found that fiber-form nanostructures are formed on the surfaces oftungsten (W) and other metals by helium (He) plasma irradiation [1]. From the viewpoint ofindustrial application, a technology for high-speed formation of fiber-form nanostructures using
a high-density He plasma generated by a compact device is desirable. So far, we have succeededin forming fiber-form nanostructures using He arc discharge plasma irradiation under a gas
pressure of 5 kPa, where collisions between ions and neutral particles in the sheath cannot be
neglected.
One of the properties of fiber-form nanostructures is their high thermal radiation properties.
However, there is a problem that nanofibers shrink under high temperature without He
irradiation [3]. In this study, in order to improve the thermal radiation properties at hightemperatures, we formed micron-sized He bubbles/holes structures [4] obtained by irradiating
He plasma at a higher temperature than fiber-form nanostructure formation.
In this experiment, a DC He arc discharge (discharge voltage: 36 V, discharge current: 34
A) was generated between W electrodes placed in a vacuum vessel. The He gas flow rate andgas pressure were 1 L min-1 and 5 kPa, respectively. A W thin plate sample (10 mm × 15 mm
× 0.05 mm) was inserted into a He arc discharge and irradiated for 2 hours, as shown in Fig. 1(a). In addition, the W sample temperature under He arc irradiation measured with a radiation
thermometer was obtained to be approximately 2000°C. A biasing voltage of -60 V was applied
between the W sample and the vacuum chamber wall tocontrol the incident He ion energy on the W sample
surface.
Fig. 1 (b) shows an FE-SEM image of the W surface
after the He arc plasma irradiation. It can be found that
open holes of He bubbles with a diameter of about 1 to
2 m are formed on the W sample surface. On the other
hand, the diameter of the open He bubbles/holes formed
at a W sample temperature of about 1550°C was lessthan 0.5 m, indicating that larger-sized bubbles/holes
are formed at higher sample temperatures.
Fig. 1(a) He arc irradiation, (b) He[1] S. Takamura et al., Plasma Fusion Res. 1, 051(2006).
[2] Y. Kikuchi et al., J. Appl. Phys. 131, 123301 (2022).
[3] T. Miyamoto, S. Takamura and H. Kurishita, Plasma
Sci. Technol. 15, 161 (2013).
[4] S. Takamura, J. Nucl. Mater. 466, 239 (2015).

bubbles/holes structure formed on the
W surface (ion flux: 2×1022 m-2s-1,
surface temperature: about 2000°C,
bias voltage: - 60V)

P-16

Simulation Development for the Next Stage of Plasma-Material Interaction
Atsushi M. Ito1,2, Arimichi Takayama1,2, and Yuto Toda2
1

National Institute for Fusion Science, National Institutes of Natural Sciences
322-6 Oroshi-cho, Toki 509-5292, Japan
ito.atsushi@nifs.ac.jp
2

Graduate Institute for Advanced Studies, SOKENDAI
322-6 Oroshi-cho, Toki 509-5292, Japan

We had been developed the several simulation codes to advance the understanding of theplasma-material/wall interaction (PMI/PWI) phenomena by focusing the classify themechanisms in atomistic scale. In the presentation, we introduced our simulation codes to findnew collaboration partners. In addition, we would like to disclose our future plans for codedevelopment, along with the next PMI research agenda we have in mind.
For the sputtering on surfaces, the Binary Collision Approximation (BCA) is better not onlyin point of calculation speed but also in the reliability of interatomic potential for high energy
collision. We have been tackle the modernization of BCA in the BDoG[1] code, especially highaccuracy interatomic potential, ReGZ potential[2], was developed and we demonstrate that therecoil cutoff energy, which is corresponding to the sputtering threshold energy, should be
moderated by using the Density Functional Theory (DFT). The DFT is better to estimate themicroscopic property in viewpoint of nanomaterial. Moreover, to just use the code, the DFT iseasy rather than Molecular Dynamics (MD) because users need only input the atomic
coordinate and a few parameters. MD requires not a little customization of the code and coding
to analyze the results of dynamics. We can support the partners to start the DFT and provide atuning patch[4] to run the OpenMX code[3] on the vector architecture super computer.
For future simulations in PMI/PWI, we are planning two directions: the first is to further
improve the validity between simulation and experiment. The interesting feature of PMI/PWI
is the gap of time- and space-scales. By using well controlled plasmas, nanomaterials are
generated in microscopic space-scale, while the their generation need seconds and minutes
which is relatively macroscopic time-scale[5]. One solution for this gapped-scale problem isthe hybrid simulation. The BCA-MD-KMC hybrid method for the helium plasma induced fuzz
can achieve 1 minutes or more in elapsed time[6]. An important scheme is to replace some of
the MD calculations with KMC or BCA. For versatility, it is important to develop the latticefree and on-the-fly KMC that can represent a wider variety of atomic motions. The second
direction is to clarify quantum electron dynamics in PMI/PWI phenomena. Almost previous
simulations were performed under the assumption that all particles are charge neutral becauseof theoretical limitation. The true pictures of PMI, including the neutralization process of ionsflying from the plasma onto surfaces, the electron stopping power for the ion penetrating into
the material, and so on, are still unclear. This problem can also be a frontier in terms ofnanoscale plasma picture, and we have been trying with the Time-Dependent Density
Functional Theory (TDDFT) simulation.
[1] A. M. Ito, A. Takayama, H. Nakamura, Plasma Fusion Res. 13, 3403061 (2018).
[2] A. M. Ito, A. Takayama, Y, Toda, Jpn. J. Appl. Phys. 62, SL1012 (2023).
[3] T. Ozaki, Phys. Rev. B. 67, 155108, (2003).
[4] A. M. Ito, et al., Plasma Fusion Res., 15, 1203085 (2020).
[5] A. M. Ito, JSAP Rev. 2023, 230412 (2023).
[6] S. Kajita, A. M. Ito, K. Ibano, J. Appl. Phys. 132, 181101 (2022).

P-17

Visualization of metastable helium distribution
using ghost imaging absorption spectroscopy
Ryusei Koyama and Mitsutoshi Aramaki
Nihon University, Graduate School of Industrial Engineering
Narashino, Chiba 274-0072, Japanciry23022@g.nihon-u.ac.jp
Ghost imaging is a method that employs a single-pixel detector such as a photodiode to capture
an image of an object [1]. We are developing a novel 2-D absorption spectroscopy method byintegrating computational ghost imaging (CGI) with traditional absorption spectroscopy. Figure
1 shows a schematic diagram of CGI. Structured right with a computer-generated random
structure 𝐼r (𝑥, 𝑦) is irradiated onto an object with a transmittance distribution 𝑇(𝑥, 𝑦). The
transmitted light is focused on a photodiode (PD) by a lens, and a PC records the integrated
intensity 𝑏𝑟 . 𝑇(𝑥, 𝑦) is obtained by the following calculation.
𝑇(𝑥, 𝑦) =⟨𝑏𝑟 𝐼𝑟 (𝑥, 𝑦)⟩ − ⟨𝐼𝑟 (𝑥, 𝑦)⟩⟨𝑏𝑟 ⟩,|⟨𝐼𝑟 (𝑥, 𝑦)⟩|2(1)where 〈⋯ 〉 represents an ensemble average formeasurements from 𝑟 = 1 to N. In addition toeliminating the need for an expensive camera, thismeasurement technique offers noise tolerancecomparable to lock-in detection. Furthermore, it has
the potential to be developed into an absorption
spectroscopy method with spatial resolution in theline-of-sight direction. This is accomplished byfocusing the structured light in a plasma.

Light Source
PD

probe

Structured Light (#r) Transmittance
Reconstructed
Image
PC
Computer Generated Pattern

PC

P

Cross-correlation

Fig.1 Schematic diagram of CGI

Figure 2 shows a helicon wave plasma device
developed to study a detached plasma. A ghost
imaging absorption spectroscopy system has beendeveloped to image the distribution of metastable
helium atoms near the end plate of the helicon wave
plasma (Fig. 3). We used a 1083nm DFB laser as alight source to excite metastable helium atoms. The
Fig.2 Helicon wave plasma device.
laser beam is converted to structured light by the
DMD. The structured light is focused
into a plasma, and the integration of thetransmitted light is observed by the lens
Diffusersystem and a PD. By calculating eq. (1),Collimator
Plasmawe obtained an image of the metastablePDhelium atom distribution. Details of theDMDimaging system and measurement results
f 100, Φ 75
f 50, Φ 75
f 100, Φ 75
will be reported.
NA 0.37
NA 0.75
NA 0.37[1] J. H. Shapiro, Phys. Rev. A 78,
Fig.3 Ghost imaging absorption spectroscopy system.
061802(R) (2008).

P-18

Analysis of Scattering of UV Vortex from Helix Conductor Using MoM
Hideki Kawaguchi1, Masahiro Katoh2 and Koichi Matsuo2
1

Muroran Institute of Technology
27-1, Mizumoto-cho, Muroran 050-8585, Japankawa@muroran-it.ac.jp
2

Hiroshima University, Hiroshima Synchrotron Radiation Center,
1-3-2 Kagamiyama, Higashi-Hiroshima City, Hiroshima 739-8511, Japan

Circular dichroism is effectively used for observation and idetification of fine structure ofchiral materials such as protein, DNA and so on. Then it is pointed out that the phenomena of
the circular dichroism appear as a result of interaction between angular momentum of incident
circular polarized (CP) wave field and the chiral material[1]. During the last decade, so-called
optical vortex has attracted strong attentions since it was shown by L.Allen in 1992 that the
optical vortex carries well-defined orbital angular momentum which is much stronger than thatof standard plane wave. Accordingly it is predicted that optical vortex dicroism can be used for
identification of chiral material structure effectively. Indeed experimental study on the opticalvortex dichroism using UV light is now planing.
In this paper, the UV vortex dichroism is investigated by using numerical simulation. Thenthe wavelength of UV light is much larger than typical size of the protein. This means the finitedifference time-domain (FDTD) method, which is the most popular numerical scheme for the
scattering phenomena, is not suitable. We here consider to use the method of moments (MoM)
in this work. Then the chiral material such as the protein is regarded as infinitesimally thinhelical conductor, and electric field E(ω,t) produced by induced surface current Kl along thethin conductor is expressed by the following frequency domain integral equation, EFIE,
E ( , x )  Eext ( , x ) 
i x  x ' 
Kl l
K 
1
1

c
e
i
i
( x  x ') l  dS '


4 S

l 
x  x'
(1)

where l is normal tangential vector of the thin conductor.
In Fig.1, distributions of Kl on the helical thin conductor and radiation patterens are depicted
when the conductor is illuminated by 190nm vortx field with toprogical charge l = 1, (a) leftand (b) right CP. Big difference in radiation power of scattered field appears for (a) and (b).
[1] S.S.Andrews and J.Tretton, J.Chem.Educ. vol.97 (2020), pp.4370-4376.

Acknowledgement
This work was supported by JSPS KAKENHI Grant Number 23H04597.
incident wave

distribution of surface
current intensity

λ = 190nm

incident wave

distribution of surface
current intensity

λ = 190nm

radiation power = 3.0716e-028(scattered field)

radiation power = 1.5237e-023(scattered field)
radiation pattern(a) incident wave of l = 1, left CP

radiation pattern(b) incident wave of l = 1, right CP

Fig.1: MoM analysis of scattering of UV vortex wave from helical thin conductor.

P-19

Evaluation of Propagation of Millimeter Wave Vortex Using FDTD Method
Chenxu Wang1, Hideki Kawaguchi1 and Hiroaki Nakamura2
1
Muroran Institute of Technology
27-1, Mizumoto-cho, Muroran 050-8585, Japankawa@muroran-it.ac.jp
2
National Institute for Fusion Science,
322-6 Oroshi-cho, Toki-city, Gifu 509-5292, Japan

It was pointed out that millimeter wave vortex can propagete in magnetized weakly ionizedplasma, in which normal plane wave can not propagete due to cut-off condition[1]. Thisphenomena may lead to more efficient plasama heating than that of conventional plasma
heating by corrugated waveguide HE11 mode millimeter wave since the millimeter wave vortex
can inject wave power to not only propagetion region but also the cut-off region in the plasma.
Then the millimeter wave vortex was assumed to be Lagarre-Gauss (LG) mode vortex in theoriginal work. In this paper, propagation of the millimeter wave vortex of corrugated waveguidehybrid mode [2] is evaluated by finite-difference time-domain (FDTD) method.
The FDTD analysis in 3D grid space consists of two parts, time domain calculation ofelectromagnetic wave fields E(x,t), H(x,t) based on Maxwell's equation, and behavior ofpolarization P(x,t) and current density J(x,t) based on the Drude-Lorentz model.
The numerical model is depicted in Fig.1(a). It is assumed that the hybrid mode millimeter
vortex is excited inside the corrugated circular waveguide and illuminated to the plasma region
located at downstream. A numerical example of the propagation of the millimeter wave vortex
in the magnetized plasama is shown in Fig.1(b). It is also found by the FDTD simulation thatplane wave of HE11 mode can not propagate in the plasma region with the same condition of
Fig.2, which means that similar phenomena as in [1] can occur even for the hybrid mode vortex.
[1] T. Tsujimura and S.Kubo, Phys. Plasmas, 28, 012502 (2021).
[2] H. Kawaguchi, S.Kubo, H. Nakamura, IEEE MWTL, Vol.33. No.2, pp.118-121, (2023).

Acknowledgement

HEmn mode inputThis work was supported by JSPS KAKENHI Grant Number 23H04609.

HEmn mode
millimeter wave vortex

corrugatedcircularwaveguideplasmaregionyxz(a) numerical model(b) E field intensity distribution in y-z plane
Fig.1: FDTD analysis of millimeter wave vortex propagation in magnetized plasma.

P-20

Observation of Global Structural Changes in Two-dimensional Emission
Profiles Associated with Attached and Detached Plasma Transitions
Yuta Uematsu1, Hideki Kaizawa1, Jielin Shi1,2, Hirohiko Tanaka1,3,
Shin Kajita4, Noriyasu Ohno1
Graduate School of Engineering, Nagoya University, Furo, Chikusa, Nagoya 464-8603, Japan
uematsu.yuta.g6@s.mail.nagoya-u.ac.jp
2
School of Physics, Dalian University of Technology, Dalian 116024, China
3
Institute of Materials and Systems for Sustainability, Nagoya University, Nagoya 464-8603, Japan
4
Graduate School of Frontier Sciences, the University of Tokyo, Kashiwa, Chiba 277-8561, Japan1

In fusion power reactors, the heat flux to the divertor plate is extremely high. One of thesolutions to reduce this heat load is generating detached plasmas, in which the plasma isneutralized by increasing the gas pressure near the divertor plate. Detailed measurements ofplasma distribution are necessary to understand property of detached plasmas. In this study,
global emission profiles of attached and detached helium plasmas were measured by using a
2D spectroscopic measurement system in the radial and axial directions in the linear divertor
plasma simulator NAGDIS-II.
Figure 1 shows an overview of the two-dimensional spectroscopy system developed.
Emission from the plasma is reflected by a mirror in the head and introduced into an opticalfiber via a collimating lens. The optical fiber is connected to a spectrometer. The head can be
moved in the axial direction and rotated in the azimuthal (θ) direction.
Figure 2 shows 2D distributions of the emission from helium atoms at a wavelength of
501.4 nm with different gas pressures. The target plate is located at z = +10 mm. It is clearlyobserved that the plasma transitions fromattached to detached plasma as the gaspressure increases. This data can betransformed to the local emission
intensity by applying the Abeltransformation. The 2D distribution ofelectrondensityandelectrontemperature will be analyzed bycomparing with the collisional radiativeFig.1 2D spectroscopic measurement system.
model.

Fig.2 2D emission distributions with different gas pressures. (31P-> 21S, 501.6nm)

P-21

Formation of helium-tungsten co-deposition layers andspectroscopic measurements during sputtering
Masanori Yamamoto1*, Kiho Tabata1, Hirohiko Tanaka2, Shin Kajita3, Quan Shi3
and Noriyasu Ohno1
1

2

3

Department of Electrical Engineering, Graduate School of Engineering, Nagoya University,
Furo, Chikusa, Nagoya 464-8603, Japan*yamamoto.masanori.v7@s.mail.nagoya-u.ac.jp

Institute of Materials and Systems for Sustainability, Advanced Measurement Technology Center,
Nagoya University, Furo, Chikusa, Nagoya 464-8603, Japan

Department of Advanced Energy Engineering, Graduate School of Frontier Sciences, The University of Tokyo,
5-1-5 Kashiwanoha, Kashiwa, Chiba 277-0882, Japan

Fusion power generation is expected to be the key to realize a decarbonized society. In
fusion reactors, tungsten (W), which has a high melting point and a low sputtering rate, will be
used as the wall material. A co-deposition layer composed of W and gases such as hydrogenand helium (He) will be formed on the wall , but its physical prparties are not well understood.
In this study, we used the compact
plasma device called Co-NAGDIS (Fig. 1)
to simulate a reactor-wall environment withthe formation of a W-He co-deposition layer[1]. A W sample was exposed to a steadystate He plasma. At the same time, W wire
negatively biased at -300 V was placed in
front of the sample to feed the sputtered W
onto the sample. Sample temperature wasadjusted by plasma heating and air cooling.
The porocity of the co-deposition layer was
evaluated by the thickness and mass change.

Fig. 1: A schematic of the experiment setup.
After forming the co-deposition layer,
we investigated the sputtering property of the co-deposition layer by argon (Ar) plasma
exposure as measuring the evolutions of the W and Ar line emissions with a spectrometer. As
a result, it was found that the ratio of WI/ArII was ~80% lower on the co-deposition layercompared to the bulk, suggesting that the co-deposition layer has a lower spttering rate.
[1] S. Kajita et al, J. Nucl. Mater. 540 (2020) 152350.

P-22

A preliminary kinetic study on plasma flow in open magnetic systems
using a quasi-one-dimensional particle-in-cell model
Kazuma Emoto,1 Satoshi Togo,1 Yoshinori Takao,2 Kazunori Takahashi,3,4Isao Katanuma,1 and Mizuki Sakamoto1
1

2

Yokohama National University, Division of Systems Research,
Tokiwadai 79-5, Hodogaya-ku, Yokohama 240-8501, Japan3

4

University of Tsukuba, Plasma Research Center
Tennodai 1-1-1, Tsukuba 305-8577, Japanemoto@prc.tsukuba.ac.jp

Tohoku University, Department of Electrical Engineering,
Aoba 6-6-05, Aramaki, Aoba-ku, Sendai 980-8579, Japan

National Institute for Fusion Science, Plasma Apparatus Unit,
Oroshi-cho 322-6, Toki 509-5292, Japan

Open magnetic systems are widely applied to plasma devices to confine and extract plasmas,
e.g., electric thrusters [1] and divertor simulations [2]. In open magnetic systems, the plasmapressure is converted into directional plasma flow according to the momentum conversion.
For electric thrusters, a two-dimensional numerical model of open magnetic systems has
been employed, and the plasma physics in open magnetic systems has numerically been
investigated using particle-in-cell (PIC) and Monte Carlo collisions (MCC) techniques, where
the electrons and ions were treated as particles in the simulations [3]. The PIC simulations in
the two-dimensional model have successfully clarified the mechanisms of plasma accelerationand thrust generation. However, the two-dimensional PIC model has a large calculation cost,
and the high-density and large-size plasmas have not been investigated yet.
To reduce the calculation cost and simulate high-density and large-size plasmas, quasi-onedimensional PIC simulations in open magnetic systems are under development. The axial sizein the quasi-one-dimensional model is extended to several tens of centimeters, whereas that in
the previous two-dimensional model was several centimeters. Furthermore, the hightemperature plasmas are also simulated in the quasi-one-dimensional kinetic model, where theplasma temperature of several tens of electron volts and an open magnetic field of several teslas
are employed. In the conference, preliminary results obtained from the quasi-one-dimensional
PIC model will be reported and discussed with axial plasma profiles and velocity distributions.
This work was partly supported by JSPS KAKENHI Grant Number 23H05442 and The
Futaba Foundation. The computer simulation was performed on the A-KDK computer system
at Research Institute for Sustainable Humanosphere, Kyoto University. This research ispartially supported by Initiative on Promotion of Supercomputing for Young or Women
Researchers, Information Technology Center, The University of Tokyo.
[1] K. Takahashi, Rev. Mod. Plasma Phys, 3, 3 (2019).
[2] Y. Nakashima, et al., Nucl. Fusion, 57, 116033 (2017).
[3] K. Emoto, K. Takahashi, and Y. Takao. Phys. Plasmas, 28, 093506 (2021).

P-23

Porous silicon produced with helium plasma for lithium-ion battery anode
Kiho Tabata 1, Shin Kajita 2, Teruya Yamada 3, Kodai Masumoto 3, Giichiro Uchida 3,
Hirohiko Tanaka 1,4, Noriyasu Ohno 1
1

Graduate School of Engineering, Nagoya University, Furo, Chikusa, Nagoya 464-8603, Japantabata.kiho.j3@s.mail.nagoya-u.ac.jp
2
Graduate School of Frontier Sciences, the University of Tokyo, Kashiwa, Chiba 277-8561, Japan
3
Graduate School of Science and Technology, Meijo University, 1-501, Shiogamaguchi, Tenpaku, Nagoya 4688502, Japan
4
Institute of Materials and Systems for Sustainability, Nagoya University, Nagoya 464-8603, JapanThe lithium-ion battery is a rechargeable secondary battery that can be used repeatedly
and is required to have high capacity for use in electric vehicles. The capacity of a lithium-ion
battery is highly dependent on the material used for the battery’s negative electrode, and silicon,
which has a theoretical capacity 10 times greater than that of graphite, is being considered as a
candidate for higher capacity. However, there is a serious problem when silicon is used: thecharge-discharge cycle causes rapid volume expansion, causing peel off of the silicon from theelectrode. As a result, the performance drops rapidly after several charge cycles. In contrast,
previous studies [1, 2] reported that nanostructured or porous silicon can prevent selfdestruction and suppress the performance degradation due to the number of cycles.
In this study, a compact plasma device CoNAGDIS was used to fabricate the negative electrode. By
sputtering silicon with high-density helium plasma, several
μm of silicon with fine or porous structure was deposited on
the substrate. Figure 1 shows the surface structure withsilicon deposition. It was observed that the surface structure
varied greatly depending on the experimental conditions.
Then, we investigated how the different
morphology of the silicon structures relates to the battery
performance. Figure 2 shows the battery
capacity up to ~100 times. It is found thatthe fabricated samples have greatly
different
performances.
The
best
performing sample (sample 2) successfully
maintains its capacity more than five times
better than that of conventional materials
after more than 100 charge cycles. We
investigated what kind of experimental
condition and surface structure would resultin a high-capacity battery.
[1]Peng Li et al. Energy Storage Materials,
35, 550-576 (2021)[2] Lin Sun et al. Energy Storage Materials,

Fig1. Surface structure of Si46, 482-502 (2022)
Fig2. The battery performance of several samples

P-24

Phase Structure and Angular Momentum of Cyclotron Radiation
Masahiro Katoh1,2, Hideki Kwaguchi3
1

2

Hiroshima Synchrotron Radiation Center, Hiroshima University
2-313 Kagami-yama, Higashi-hiroshima 739-0046, Japanmkatoh@hiroshima-u.ac.jp

Institute for Molecular Science, National Institutes of Natural Sciences,
38 Nichigo-naka, Myodaiji-cho, Okazaki 444-8585, Japan3

Muroran Institute of Technology
27-1, Mizumoto-cho, Muroran 050-8585, Japan

Radiation field emitted from electrons, which can be described by Liénard–Wiechert
potentials, has characteristic spatial and temporal structures which reflect the electron motion.
One of the simplest cases is cyclotron radiation. Electrons are making circular/helical motion
in a uniform magnetic field and radiate. They lose not only their energy but also their angularmomentum through the radiation. Therefore, both the energy and angular momentum should be
carried away by the electromagnetic wave. It is well known that electromagnetic wave carries
energy, which is described by Poynting vector. It is also well known that circularly polarized
electromagnetic wave carries angular momentum which corresponds to spin angularmomentum. On the other hand, it had been less known that electromagnetic radiation carries
orbital angular momentum until 30 years ago. In 1992, Allen et al. discussed that LaguerreGaussian beam, which has helical phase structure, carries orbital angular momentum [1]. Since
then, such a light beam called optical vortex has attract interests of researchers and has been
investigated theoretically and experimentally [2].
In this presentation, we review our previous researches on the radiation field emitted fromelectrons in circular/helical motion [3, 4, 5]. Based on the classical electrodynamics, we showthat such radiation field generally possesses helical phase structure and carries both spin andorbital angular momentum. Such topological structure is caused by the relativistic effect. As
another consequence of the relativistic effect, the radiation field contains harmonics. Eachharmonic component carries well-defined angular momentum depending on the number of
harmonic. We attempt an intuitive understanding of this phenomenon.
Electrons in circular/helical motions can be seen in various physical situations such as
nuclear fusion plasma, electron accelerators, astrophysical phenomena and so on. They radiate
electromagnetic waves possessing helical wavefront and carrying orbital angular momentum.
Consequently, such vortex radiation is ubiquitus not only in laboratories but also in the universe.
Moreover, we can realize powerful sources of vortex radiation in the entire wavelength range
from radio wave to gamma-rays [6, 7, 8].
[1] L. Allen et al., Phys. Rev. A 45, 8185 (1992)[2] Y. Shen et al. Light: Science & Applications, 8, 90 (2019)[3] M. Katoh et al., Phys. Rev. Lett. 118(9) 094801 ( 2017).
[4] H. Kawaguchi, M. Katoh, Prog. Theor. Exp. Phys. 2019(8) 083A02 (2019).
[5] E. Salehi, M. Katoh, J. Adv. Simulat. Sci. Eng. 8, 1, 87 (2021).
[6] Y. Goto, S. Kubo, T. Tsujimura, T. Kobayashi, Plasma and Fusion Res., 17, 2401007 (2022)[7] M. Katoh et al., Sci. Rep. 7, 6130 (2017)[8] Y. Taira, T. Hayakawa, M. Katoh, Sci. Rep. 7, 5018 (2017)

P-25

Spectroscopic measurement of microwave atmospheric pressure nitrogenplasma and the effect of vapor addition on the hydrophilicity of polystyrene
surface
Kazutaka Onoda1, Hwangbo Dogyun2, Katsuhiko Shiraishi3 and Mizuki Sakamoto1
Plasma Research Center, University of Tsukuba,
1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8577, Japan
onoda_kazutaka@prc.tsukuba.ac.jp
12Faculty of Pure and Applied Sciences,
Plasma Research Center, University of Tsukuba,
1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577, Japan
3

Research & Development Group, Hitachi, Ltd,
7-2-1 Omika, Hitachi 319-1221, Japan

Controlling the hydrophilicity of cell culture plates has been a key issue in improving cell
culture efficiencies. Polystyrene (PS) is one of the most widely used cell culture plates, andcontact angle control using PS has been studied for many years [1,2]. In particular, atmosphericpressure plasma jet (APPJ) has accelerated the application of plasma in surface hydrophilicity
control, due to its low fabrication cost and ease of development. In this study, a microwave
APPJ is developed and the effect of the plasma on the hydrophilic properties of PS plates isevaluated.
This study focused on three main aspects. First, we generated an atmospheric microwave
plasma using nitrogen (N2) gas. Sometimes water vapor was added to the working gas, whichleads to changes in the plasma components. To evaluate the plasma characteristics,
spectroscopy was performed with a compact visible spectrometer (AvaSpec-ULS4096CL-EVO,
Avantes), measuring the spectra emitted from the plasma source and from the remote jet region.
The commercial software Specair was used to identify the plasma species and to evaluate theexcitation temperatures. Subsequently, PS samples with different pretreatments were exposed
to different types of plasma jets for 1-4 min, then the surface hydrophilicity was analyzed by
the contact angle method. In addition, the surface composition due to plasma irradiation wasinvestigated by X-ray photoelectron spectroscopy (XPS). Then, the temporal changes of thecontact angles were measured with the samples in different conditions (in ultrapure water,
vacuum, air etc.) to see the effect of storage conditions on the hydrophilicity.
The plasma species and excitation temperatures of the plasmas were influenced by the
input power, gas flow rate and vapor concentration. The spectra consisted of NO, OH, NH as
well as N2. The ratio of NO, OH, NH to the total components increased with the vapor
concentration, while the intensities of the spectra decreased. The most hydrophilic surface wasproduced with pure N2 working gas. On the other hand, when the surface was exposed to theplasma with N2+vapor mixture, the contact angle decreased only slightly compared to thepristine surface Relevant XPS analysis also confirmed the changes in surface composition due
to N2 plasma irradiation, demonstrating the formation of hydrophilic bonds.
[1] Bo-Lennart Johansson et al., Journal of Applied Polymer Science, 86, 2618-2625 (2002).
[2] Esmaeil Biazar et al., International Journal of Nanomedicine, 6, 641-647 (2011).

P-26

Effect of argon additive in Cs-free negative hydrogen ion source
Kaito Miura1, Ryuichi Onuma1, Naonori Okada1 and Akira Tonegawa1
1Tokai University, Kitakaname,Hiratsuka,Kanagawa 259-1292, Japan
9bsp1214@gmail.com,

Most neutral beam injection (NBI) systems in fusion devices use Cs-type negative ion
sources, which require careful control and are difficult to operate for long periods of time. Asan alternative method, we are developing a volume-production (Cs-free) type negative ion
source using sheet plasma[1-4]. In this Cs-free negative ion source, the current ratio of coextracted electrons to extracted ions JEG /JH- must be kept below 0.5-1.0 to prevent high heatload on the extraction electrode (EG). Previously, Cs-free negative ions have been proposedusing a high-density magnetized sheet plasma produced by TPDsheet-U [1,2]. The purpose ofthis study is to increase the negative ion current and to reduce the co-electron current by using
the following two methods; (1)argon addition method and (2)second anode bias method (Fig.1).
Ar gas additive is effective when the discharge current is low. However, the effect of Ar
addition is small because the electron temperature increases with increasing discharge current
and the state of Ar shifts from a metastable state to an ionized state, so that resonant excitationof molecular hydrogen by Ar metastable atoms does not occur.
By applying a positive bias to the second anode, the negative ion current Jc was successfullyincreased while keeping JEG/Jc below 1, even when the discharge current was increased. This
indicates experimentally that the second anode bias method enhances the effect of Ar gas
addition (Fig.2).

B

Fig.1 Schematic diagram of Cs-free
negative ion source TPDsheet-U.

Fig.2 Characteristics of Jc, JEG,
JEG/Jc vs Ar gas flow rate.

[1] K.Kaminaga, et. al., Rev. Sci. Instrum. 91 (2020) 113302.
[2] A.Tonegawa, et. al., Nucl. Fusion 61 (2021) 106030.

P-27

Correlation of tungsten surface morphology changes and deuterium
absorption properties by deuterium plasma exposure with pulsed heat load
Ryo Sasaki1, D. Hwangbo1, K. Saito1, K. Onoda1, S. Murakami1, H. Yoshida1, M. Sakamoto1
1

Plasma Research Center, University of Tsukuba
Tennodai, Tsukuba, Ibaraki 305-8577, Japansasaki_ryo@prc.tsukuba.ac.jp

As a plasma facing material (PFM) in future fusion reactors, tungsten (W) must withstandparticle and heat loads from collisions by hydrogen isotopes and helium ions, as well as neutronloading. In the study of fusion-relevant plasma-surface interaction (PSI), tritium absorption andsurface modification of PFMs are important research issues related to the lifetime of PFMs,
operational stability of fusion reactors and fuel efficiency [1].
Under high flux plasma irradiation conditions, surface modification of W can cause thechanges in the implantation of hydrogen isotope ions, and both the surface modification and theamount of hydrogen isotope absorption strongly depend on the irradiation parameters such as
the target temperature, the incident ion flux and the irradiation fluence. In this study, we focusedon changes in the W surface structure and relevant hydrogen isotope absorption characteristics
due to changes in sample temperature. Specifically, deuterium (D) plasma and pulsed laser
irradiation were simultaneously applied to a W sample to examine the surface modification andD absorption of a W sample undergoing instantaneous temperature changes.
Experiments were conducted with three W samples called (a), (b) and (c), respectively. All
three samples were irradiated plasmas with D ion flux of 6 × 1021 D/(m2 . s) and the incident
fluence was 2 × 1025 D/m2 . The irradiation temperature for (a) was 617 K. For (b), the plasma
was irradiated under the same conditions as (a) with an additional heating by Nd:YAG pulsed
laser, and the sample temperature was 644 K. For (c), the sample temperature was 644 K. The
surface condition of W after plasma irradiation was observed by scanning electron microscope(SEM), and the D absorption amount was measured by thermal desorption spectroscopy (TDS).
Figure 1 shows the results of D amount retained indesorbed from the samples with the three different
irradiation conditions. Resultant surface mophologies arealso shown. Fig. 1(a) and (c) are the results of D plasma
irradiation alone, showing that the blisters were formed on
the surface and D absorption was higher than that of Fig.
1(b), where W was exposed simultaneously to the Dplasma and the pulsed laser. The total D retention for the
sample (b) was one fifteenth to the sample (c) with D
plasma only, while no surface changes were observed at
the same time. These results suggest that intermittent
temperature changes caused the suppression of blistering Fig. 1: Results of D absorption
on the surface, leading to reduced D retention into W body. amount and surface morphology
after irradiation. (a) and (c) are[1] J. Roth, E. Tsitrone, and A. Loarte, Nucl. Instr. and exposed to the sole D plasma, andMeth. in Phys. Res. B 258 (2007) 253–263(b) to the simultaneous D plasmaand pulsed laser irradiation.

P-28

The appearance of deuterium low temperature desorption at modified
tungsten surfaces under helium pre-exposure conditions
Kota Saito1 , D. Hwangbo1 , H. Yoshida1 , K. Onoda1 , R. Sasaki1 , S. Murakami1 , T. Okugi1 ,A. Kataniwa1 , H. Kida1 , M. Sakamoto1 and M. Sakamoto1
1

Plasma Research Center, University of Tsukuba
Tsukuba, Ibaraki 305-8577, Japansaito_kota@prc.tsukuba.ac.jp

Tungsten (W) as the divertor and the first wall material in future nuclear fusion reactors will
be exposed to hydrogen isotopes-helium (He) admixture plasmas. Estimating the amount ofhydrogen isotopes absorbed in a W body during/after fusion operation is therefore ofimportance for the reactor safety regulation as well as to realize the steady state operation [1].
It has been known that He bubbles and He clusters are easily created and stabilized in a W
bulk space. Furthermore, fiberform nanostructure, so-called 'fuzz', grows on a W surface [2].
Fuzz and He bubble themselves and W lattice defects made by them has been a long-standing
issue for their role in the hydrogen isotopes retention. It is generally understood that preirradiated He defects can act as near-surface diffusion barrier against hydrogen isotopes. On theother hand, a recent study has shown that deuterium (D) can agglomerate and settle inside a He
bubble, implying that the He defects can play a trapping site of hydrogen isotopes [3].
A previous study has also shown that D and He desorption peaks existed at ~350 K on fuzz
samples, while the surface temperature during the plasma exposure was much higher [4]. The
reason for this desorption is still unclear. Our study aims to understand a potential mechanismof the low temperature desorption on W.
For experiment, the compact RF linear plasma device
APSEDAS was used. Three W samples were prepared,
named (i) Pristine W, (ii) Bubble W and (iii) Fuzz W. The
sample (ii) and (iii) were pre-exposed to He plasmas withdifferent conditions to form He bubbles and Fuzz on thesurfaces, respectively. Then, D plasma was set and thesamples were retracted ~10 cm away from the plasma
center, being exposed to not D ions but only D atoms
reflected from the vacuum vessel to see if the surface
absorption by D atoms are effective. Fig. 1 shows the resultsof thermal desorption spectra (TDS) of the samples. First, D
desorption peaks around ~360 K appear by D atom collision,indicating that the desorption is partly due to the surface
absorbtion. Second, D desorption from the sample (i) is 50
or 100 times lower than (ii) or (iii) samples, which isestimated He effect.
The effect of He desorption and fuzz nanostructure to Fig. 1: D desorption spectra
low temperature D desorption peak should be more for three W samples at 300researched.
400 K.
[1] T. Tanabe, Tritium: Fuel of Fusion Reactors (Springer, 2017).
[2] S. Takamura et al., Plasma Fusion Res., 1, 051 (2006).
[3] M. Miyamoto, et al., Nucl. Mater. Energy, 36, 101484 (2023).
[4] M. Yajima, et al., J. Nucl. Mater., 449, 9-14 (2014).

P-29

Investigation of Reaction Process during Combined Seeding of
Nitrogen and Hydrogen in Divertor Simulated Plasma
Takuma OKAMOTO, Naomichi EZUMI, Satoshi TAKAHASHI, Satoshi TOGO,
Kosuke TAKANASHI, Keishi KOUNO, Hiroto KAWAHARA, Takumi SETO,
Reina MIYAUCHI and Mizuki SAKAMOTO
Plasma Research Center, University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japanokamoto_takuma@prc.tsukuba.ac.jp

One of the challenges in realizing the fusion reactor is protecting the divertor fromenormous heat loads. The particle flux toward the divertor plates must be reduced to achieve
heat load reduction. For this purpose, forming the detached plasma through the plasma-gas
interaction is being considered [1]. The detached plasma is formed by volumetric recombination
contributing to the particle flux reduction. Recently, “Nitrogen-induced Molecular-Activated
Recombination (N-MAR)” during Nitrogen and Hydrogen seeding has been found effective inion flux reduction [2,3]. This is because Dissociative Recombination of NHx+ has higher rate
coefficients in a few electron temperatures than other recombination processes such as H-MAR,
and EIR. However, N-MAR reaction processes are complicated because multiple ions andmolecules exist [2,4]. In this study, we investigate the reaction processes during Nitrogen andHydrogen seeding in the divertor simulated plasma. We conduct the divertor simulated
experiments and the particle and reaction balance calculations.
The experiment is conducted with the Divertor simulation experimental module (D-module)
installed in GAMMA 10/PDX that is the tandem mirror device. Hydrogen plasma is generated
at t = 50 msec and sustained for 400 msec. We conducted the detached plasma experimentswith only Hydrogen seeding and the combined seeding of Nitrogen and Hydrogen. As shownin Fig.1 (a) and (b), the ion flux and electron density (ne) show “rollover”, they first increase
and then decrease. It can be seen that both the ion flux and ne are lower in the combined seeding
than in only Hydrogen seeding. In the case of the combined seeding, however, the ion flux
decreases greater than ne. This result indicates that heavy ions (NHx+, N2H+) produced in the NMAR reaction process affect the ion flux. In this presentation, we also show the results ofspectroscopic measurement and particle balance calculation.

Fig.1 Time evolution of (a) the ion flux and (b) the electron density (green circle: only Hydrogenseeding, red triangle: Nitrogen and Hydrogen combined seeding).

[1] A.W. Leonard, Plasma Phys. Control. Fusion 60, 044001 (2018).
[2] R. Perillo et al., Plasma Phys. Control. Fusion 60, 105004 (2018).
[3] N. Ezumi et al., Nuclear Fusion 59 (2019) 066030.
[4] T. Okamoto et al., Plasma Fusion Research 18, 1402047 (2023)

P-30

Electrostatic field calculation on a curved surface for gyrokinetic modelingof stellarator edge plasmas
Toseo Moritaka1, Robert Hager2, Seung-Hoe Ku2 and C-S. Chang2
1

National Institute for Fusion Science, Toki 509-5292, Japan
moritaka.toseo@nifs.ac.jp
2
Princeton Plasma Physics Laboratory, Princeton, NJ 08543, USA

The gyrokinetic model is commonly used to demonstrate plasma transport phenomena
under self-consistent field perturbations in global magnetic field equilibria. X-point Gyrokinetic
Code (XGC) is developed for whole-volume modeling of tokamaks. It utilizes an unstructured
mesh and particle-in-cell method to include the edge magnetic field and the vessel components[1]. We are developing the non-axisymmetric version of XGC, namely XGC-S. XGC-S has
been successfully applied for linear and non-linear simulations in the core regions of stellarators[2,3,4]. However, extending the gyrokinetic model to the edge regions remains challenging
because of their complex magnetic field structures. The complexity comes not only from the
non-axisymmetric configuration but also from the entangled magnetic field lines. In addition,
the magnetic field lines divert significantly from the torus direction in the helical divertor
configuration.
We present novel computational schemes to calculate electrostatic fields in the edge
region of stellarators. The scheme includes curved surface and hierarchical mesh generation.
The curved surface is generated using a numerical optimization technique to ensure it is locallyperpendicular to the confinement magnetic field. This surface effectively solves the gyrokinetic
Poisson equation with the perpendicular gradient operator. The finest mesh is generated bynumerical field line tracing on the curved surface. Magnetic field lines with long connection
lengths automatically refine important regions such as the divertor leg and the ergodic layer(Fig. 1). The iterative matrix solver using the multi-grid biconjugate gradient stabilized method
is improved for electrostatic field calculation on the hierarchical mesh. Here the Jacobian matrix
computed at each mesh vertex is considered in solving the Poisson equation on the curved
surfaces (Fig. 2).

Fig. 1 : Hierarchical mesh on the optimized
surface in the Large Helical Device

Fig. 2 : Test of the Laplacian operation using ahierarchical mesh on the unit spherical surface[1] S. Ku, C. S. Chang, R. Hager, et al., Phys. Plasmas 25, 056107 (2018).
[2] T. Moritaka, R. Hager, M. Cole, et al., Plasma 2, 179-200 (2019).
[3] M. Cole, R. Hager, T. Moritaka, et al., Phys. Plasmas 26, 082501 (2019).
[4] M. Cole, T. Moritaka, R. Hager, et al., Phys. Plasmas 27, 044501 (2020).
[5] T. Moritaka, H. Sugama, M. Cole, et al., Nucl. Fusion 62, 126059 (2022).

P-31

Development of a kinetic transport model in broken flux surfaces
J. X. Li1, T. Moritaka1,2, R. Kanno1,2, G. Kawamura1,2, R. Hager3 and C.S. Chang3
1

The Graduate University for Advanced Studies, SOKENDAI, Toki 509-5292, Japan
li.joseph@nifs.ac.jp
2
National Institute for Fusion Science, Toki 509-5292, Japan3
Princeton Plasma Physics Laboratory P.O. Box 451, Princeton, NJ 08543, USA

Modern toroidal magnetic fusion devices often have broken flux surfaces with magnetic
islands and ergodic layers generated by resonant magnetic perturbations (RMPs). Such
broken flux surfaces may play a role in the control of MHD instabilities, such as Edge
Localized Modes [1]. In the devices using RMPs, effects of broken flux surfaces on edge
turbulence and neoclassical transport are also worthy of interest. In this study, to adequately
treat the effects of these structures on kinetic transport phenomena, a kinetic model isdeveloped, based on a kinetic simulation in a toroidal plasma equilibrium including RMPs.
The X-point Gyrokinetic Code (XGC) utilizes particle-in-cell (PIC) methods with an
unstructured mesh without assuming flux coordinates for whole volume modeling oftokamaks [2]. A stellarator compatible version, XGC-S [3], can treat broken flux surfaces
under non-axisymmetric magnetic field perturbations. We use analytic circular tokamak
equilibria [4] wherein islands and ergodic layers changed gradually according to RMPs in
XGC-S and calculated the resulting transport coefficients. Additionally, we will extend thisstudy to stellarators using, for example, the equilibrium of the planned CFQS [5], and present
preliminary calculations.
The initial simulation result of calculating an electrostatic potential in a circular tokamak
plasma without RMPs is shown in the figure below. To stimulate the formation of islands, amagnetic perturbation of the form 𝛿𝛿𝐁𝐁 = ∇ × (𝛼𝛼𝐁𝐁), where α = α0 cos(𝑚𝑚θ −2𝑛𝑛ϕ) exp[−(𝑟𝑟𝑛𝑛𝑛𝑛− 𝑟𝑟 2 )2 /Δ𝑟𝑟 4 ], is applied. Here, α0 is chosen according to other parameterssuch as the mode numbers 𝑚𝑚/𝑛𝑛, θ is the poloidal angle, ϕ is the toroidal angle, 𝑅𝑅𝑎𝑎𝑎𝑎 is
the toroidal axis, and 𝑟𝑟 = �(𝑅𝑅 − 𝑅𝑅𝑎𝑎𝑎𝑎 )2 + 𝑍𝑍 2 . The kinetic modeling is performed inmagnetic structures withislands/ergodic layers generated
gradually according to the strength of
RMPs.
With an eye towards complex
stellarator geometries, we believe theability to accurately model perturbative
magnetic phenomena will be a great
asset in stellarator design and the studyof edge plasmas in magnetic fusion
devices.
Figure 1: ITG mode electrostatic potential fluctuations from a linear
XGC-S simulation with an analytic circular tokamak equilibrium

References:[1]
Kirk, A. et. al. Plasma Phys. Contr. Fusion, 55(12), 124003 (2013).
[2]
Ku, S., Chang, C. S., Diamond, P. H. Nucl. Fusion, 49(11), 115021 (2009).
[3]
Moritaka, T. et. al. Plasma, 2(2), 179–200 (2019).
[4]
Kanno, R., et al., Nucl. Fusion 58, 016033 (2018).
[5]
Liu, H. et. al. Nucl. Fusion, 61(1), 016014 (2020).

P-32

Example of Medical and Engineering Collaboration in Data Analysis in
the field of the Nuclear Fusion

Yoshihide Shibata1 , Hoshino Shinsuke2, Ryusuke Ae3, Tohru Kobayashi4and Hiromichi Hamada5
National Institute of Technology, Gifu college
2236-2, Kamimakuwa, Motosu, Gifu, 501-0495, Japan
shibata.yoshihide@gifu-nct.ac.jp
2 Shiga University of Medical Science ,3 Jichi medical University,
4 National Center for Child Health and Development,
5 Chiba University
1

Medical records such as patient data and lab data are stored in data storage in each hospitalfor medical treatment. The size of medical data stored in each hospital is increasing due tothe development of medical devices. However, physicians are not expart for data analysis,
many physicians cannot make specialized tools for large-scale analysis to analyze these
medical data. In the field of engineering, researchers often use a programing language formaking data analysis tools. We consider that a collaboration between medical andengineering could provide the new future of medical data analysis.
Kawasaki Disease (KD) is a unique disease for child and the onset mechanism has not beenclarified yet although this disease was discovered almost 50 years ago. There is large data
set for KD in Japan for research of etiology in KD, which is called nationwide survey in KD,
however large-scale data analysis such as by using AI algorism has not yet been carried out
yet. Our team was focused on this point, we made a collaborative team between medical
and engineering departments for large-scale data analysis in KD. In our activities, theepidemiology of KD during COVID-19 pandemic periods was investigated by using
nationwide survey in KD and data analysis technics in the nuclear fusion and some papaers
was published in medical journals[1-2]. In this presentation, we will explains examples of
medical and engineering collaboration in KD data analysis by using our activities.
[1] R. Ae, Y. Shibata, et. al., J. Pediatr. 2021;250: P54-60.E5.
[2] S. Hoshino, Y. Shibata, et. al., J. Pediatr. 2022;239:50-58.e2.

P-33

Synthesis of graphitic carbon nitride on carbon nanowalls
Kouta Ishigure1, Keigo Takeda1 and Mineo Hiramatsu1
1

Meijo University, Shiogamaguchi, Tempaku, Nagoya 468-8502, Japan
223427004@ccmailg.meijo-u.ac.jp

Absorbance[a.u.][3] M. Hiramatsu et al., App. Phys. Lett. 84, 4708 (2004).
[4] M.Hiramatsu et al., Jpn. J. App. Phys. 52, 01AK05(2013).
[5] Y. Bu et al., Electrochim. Acta 88, 294-300 (2013).

｛

Photocatalytic semiconductor is promising for the purification of environmental organic
pollutants because it can effectively decompose pollutants into inorganic compounds such as
CO2 and H2O. Recently, graphitic carbon nitride (g-C3N4) has attracted much attention due toits unique properties such as high chemical and thermal stability, suitable electronic band
structure for visible light responsiveness, and cost efficiency [1]. However, g-C3N4 has low
photocatalytic performance because of its low specific surface area in visible light. The g-C3N4
can be synthesized by vapor deposition polymerization using guanidine carbonate as a raw
material or electrodeposition in acetonitrile solvent, and baking dicyandiamide as raw material
has been attempted. Among these methods, vapor phase transport is known as a liquid-freemethod [2]. Carbon nanowalls (CNWs) are two-dimensional nanostructures with open
boundary edges composed of stacks of graphene sheets standing nearly vertically on thesubstrate. Due to their vertical alignment and interspacing, CNWs have large surface area andact like an electrode network [3]. We aim to develop g-C3N4-based catalytic material with large
specific surface area by combining with CNWs. In this study, we synthesized g-C3N4 on CNWs
by the vapor phase transport method using melamine.
CNW film was grown by inductively coupled plasma-enhanced chemical vapor deposition(ICP-CVD) [4] on heated (600 °C) Si substrate for 30 min. RF (13.56 MHz) power was 600 W
and a chamber pressure was kept at 15 mTorr with H2 and CH4 flow rates of 25 and 5 sccm,
respectively. Then, carbon nitride was synthesized on the CNWs using a hot-wall thermal CVD
apparatus consisting of a ceramic tube and an electric furnace. Melamine as a raw material wasplaced on Si substrate, and CNW film grown on another Si substrate was placed 10 mm awayfrom the melamine. These Si substrates were covered with aluminum foil and placed in theceramic tube. Synthesis of carbon nitride was carried out under atmospheric pressure at 600 °C
for 2 h. Synthesized product was characterized using scanning electron microscopy (SEM),
photoluminescence (PL), and Fourier-transform infrared spectroscopy (FT-IR).
Figure 1 shows FT-IR spectra of (a) CNWs, (b) product on the Si substrate where the raw
material was placed, and (c) product synthesized on CNWs. Regarding the FT-IR analysis for
g-C3N4, CN heterocyclic stretching vibration around 1240-1630 cm-1 and N-H stretchingvibration around 3250 cm-1 have been reported [5]. Clear(a)CNWabsorption peaks due to CN heterocyclic stretching(b)g-C 3N4 on Si
CN(c)g-C3N4 on CNWs
vibration and N-H stretching vibration were observed inNH
the FT-IR spectrum of the product synthesized on CNWs,
indicating the synthesis of g-C3N4 on CNWs.
[1] X. Wang et al., Nature materials 8, 76 (2009).
[2] J. Wang et al., Chem. Commun. 19, 2258-2259 (2002).
1000

2000
3000
Wavenumber[cm-1]

4000

Fig. 1 FT-IR spectra of (a) CNWs andproducts synthesized on (b) Si and (c)
CNWs.

P-34

Nitrogen addition to diamond using radical injection-CVD
Kodai Ishikawa1, Keigo Takeda1 and Mineo Hiramatsu1
1

Meijo university
1-501, Shiogamaguchi, Tenpaku, Nagoya 468-8502, Japan
223427002@ccmailg.meijo-u.ac.jp

Intensity(a.u.)

Diamond possesses excellent properties such as a wide bandgap, high thermal conductivity,and high hardness. Additionally, by doping impurities, it exhibits semiconductor characteristics,
making it a promising material for next-generation semiconductors. However, the deposition of
nitrogen-doped diamond (NDD) which exhibits an n-type conduction is relatively difficult
because the efficiency of nitrogen-doping is not so high [1] and the nitrogen-doping into
diamond tends to change the crystal structure [2]. To solve this issue, a deposition method
utilizing radical injection-CVD (RI-CVD) technique [3] has been applied in this study.
In this study, we utilized microwave plasma (MWP) (ASTeX-Type) combined withinductively coupled plasma (ICP) to deposit nitrogen-doped diamond films. By employing ICP,
we aimed to promote the dissociation of nitrogen molecules (N2), facilitating the incorporationof nitrogen-related active species into the diamond film.
Figure 1 shows the schematic of RI-CVD
system used in this study. The MWP is used forthe main CVD to grow diamond films, andreactive species generated by the remote ICP are
introduced into main plasma region. For the
MWP, a mixture of H₂ and CH₄ was used as asource gas mixture. For the remote ICP, the mainchamber is equipped with a quartz tube of 30 mm
in diameter and 250 mm long, which issurrounded by a 5-turn solenoid antenna. A carbon
rod connected to the GND is inserted into thequartz tube so that the ICP is generated even underhigh pressure (~55 Torr). A mixture of N₂ and H₂ Fig. 1 Schematic of RI-CVD apparatus(N₂/H₂ = 500 ppm) was flowed through the quartz comprising MWP and ICP
tube.
NDDs were deposited on the pretreated Si
substrate at an N₂ flow rate of 500 ppm relative to
H₂. Figure 2 compares the PL spectra of NDDs
deposited by MWP and RI-CVD; a peak at 1.68
eV was observed with and without ICP, whereas apeak due to the N-V center (2.16 eV) was clearlyobserved in the NDDs deposited by RI-CVD,
indicating that the nitrogen addition is enhanced
1.6
1.8
2
2.2
2.4
by applying RI-CVD.
E(eV)

Fig.2 Comparison of PL spectra of[1] S. Jin, et al., Appl. Phys. Lett., 65, 403
NDDs deposited by MWP and RI-CVD(1994).
[2] R. Locher, et al., Appl. Phys. Lett., 65, 34(1994).
[3] M. Hori, et al., J. Phys. D: Appl. Phys., 44, 174027 (2011).

P-35

Defluorinated degradation of per/poly fluoro alkyl substances (PFAS)
in water using non-thermal plasma
Zhe-Wei Gong1，Chih-Yu Ko1, Jang-Hsing Hsieh2 and Wen-Hui Kuan1＊
1

Department of Safety, Health and Environmental Engineering, Ming Chi University of Technology,
Taishan New Taipei, Taiwan＊

Corresponding author: whkuan@mail.mcut.edu.tw

2Center for Plasma and Thin Film Technologies, Ming Chi University of Technology, Taishan, New
Taipei, Taiwan

per/poly fluoro alkyl substances (PFAS) feature carbon chains where allhydrogen atoms have been replaced by fluorine atoms, forming strong and stablecarbon-fluorine bonds. The strength of these carbon-fluorine bonds renders PFAS
resistant to degradation under common environmental conditions, resulting in highstability. Due to the robustness of the carbon-fluorine bonds, water molecules areunable to effectively interact with them, making PFAS difficult to dissociate or
dissolve in water. This property poses potential risks to the environment and health, as
the accumulation of perfluorinated compounds can lead to environmental pollution
and potential threats to ecosystems and human health.
Non-thermal plasma technology is typically accompanied by the generation ofelectric fields and reactive chemical radicals, making it suitable for treating stubborn
pollutants. Key factors in low-temperature plasma technology include discharge
stability, the medium used, and reactor structure. Parameters such as pollutant
concentration, pH value, treatment duration, and voltage adjustment can impact
degradation efficiency.
This study employs non-thermal plasma technology as an innovative method for
defluorinated degradation of the PFAS in water. Perfluorohexanoic acid (PFHxA) waschosen as the target pollutant in the study. Experimental results demonstrated that
under positive polar electrode installation, PFHxA can be effectively degradation in
20 min. As plasma treatment progresses over time, the pH of the solution declined,facilitating fluoride degradation. Different modules yielded varying removal
efficiencies, with longer-chain fluorinated compounds possessing more carbon atoms
exhibiting hydrophobicity and rapid decomposition. Dissolved electron and argon
molecule with positive valence were believed to be the key elements for
defluorination. However, due to the hydrophobic nature of PFAS, effective aeration
was necessary to achieve optimal degradation efficiency.

P-36

Immobilization of glucose oxidase on carbon nanowalls
Jumma Kagami1, Keigo Takeda1 and Mineo Hiramatsu1
1

Department of Electrical and Electronic Engineering, Meijo University,
1-501 Shiogamaguchi, Tempaku, Nagoya 468-8502, Japan
223427011@ccmailg.meijo-u.ac.jp

Carbon nanowalls (CNWs) consist of multilayer nanographene grown perpendicularly tothe substrate, providing substantial specific surface area, excellent electrical conductivity, andchemical stability. Therefore, CNWs have potential functions as electrodes for batteries andbiosensors by applying surface modifications with metal nanoparticles and enzymes [1].
In this study, CNWs were applied to electrode materials for biofuel cells (BFCs). Glucose
oxidase (GOD) was chosen as the enzyme, and the surface of CNWs was modified with the
GOD. The enzymatic property of GOD immobilized on CNW surface was investigated using
UV spectrophotometer.
CNW films were grown on Si substrates using inductively coupled plasma-enhanced
chemical vapor deposition (ICP-CVD) system [2] with a mixture of CH4 and Ar at a pressureof 15 mTorr, a Si substrate temperature 600 ˚C, and a RF power of 600 W for 30 min. Prior to
the immobilization of oxidoreductase enzymes on CNWs, surface treatment using microwave
excited atmospheric pressure plasma jet (MW-APPJ) was carried out to modify the CNW
surface with hydrophilic groups such as carboxyl groups. Then, hydrophilized CNWs were
immersed in buffer solution (pH 6.5) containing GOD for 24 hours to modify CNW surface
with GOD.
The hydrogen peroxide (H2O2) produced by the reaction between GOD and D-glucose
react with peroxidase, 4-aminoantipyrine, and phenol, resulting in the formation of a red
quinone dye [3]. Since this red quinone dye has an absorption maximum at a wavelength of
505 nm, the amount of H2O2 produced by the reaction between GOD and D-glucose wasestimated by measuring the absorbance with a UV spectrophotometer.
Figure 1 shows the results of enzyme
activity measurements obtained by an UV
spectrophotometer for CNWs with/without
surface treatment using MW-APPJ. The
absorbance for the surface-treated CNWs
was higher than that of the CNWs without
surface treatment. Based on a calibration
curve obtained using hydrogen peroxidewith different concentrations, the amountof H2O2 produced was estimated to be 2.1 Fig. 1: Absorbance of solution after enzymatic
mM with surface treatment and 1.2 mM reaction of GOD immobilized on CNWs
without surface treatment. The surface
treatment with MW-APPJ provides hydrophilic groups such as carbonyl and carboxyl groups
to the surface of CNWs. This suggests that the amount of immobilized GOD increased due tothe dehydration condensation reaction between the carboxyl groups on the surface of the
CNWs and the amino groups of the enzyme by the condensation reagent.
[1] M. Hiramatsu, K. Shiji, H. Amano, M. Hori, Appl. Phys. Lett. 84, 4708 (2004).
[2] M. Hiramatsu, Y. Nihashi, H. Kondo, M. Hori, Jpn. J. Appl. Phys. 52, 01AK05 (2013).
[3] M. Shimomura, H. Kikuchi, T. Yamauchi, S. Miyauchi, Pure Appl Chem. 33, 1687 (1996).

P-37

Protein aggregation driven by atmospheric pressure plasma
between needle electrode and surface of albumin solution
Yukei Ishihara1,2, Tetsuji Shimizu1, and Hajime Sakakita1,21National Institute of Advanced Industrial Science and Technology (AIST),
Central2, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan
S2220826@s.tsukuba.ac.jp
2
University of Tsukuba,
1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577, Japan

Low-temperature atmospheric pressure plasma allows a surface treatment without causing
thermal damage. Due to this characteristic, low-temperature atmospheric pressure plasmas havebeen investigated for application in the biological and medical fields. As an example ofpromising applications, hemostasis by low-temperature plasma treatment was proposed [1]. In
many cases, cauterization is used to stop bleeding in surgery. However, cauterization causes
heat injury even outside of the hemostasis area. To reduce such thermal damage on tissues, theusage of low-temperature atmospheric pressure plasmas has been proposed and discussed [1].
Previous studies showed that the aggregation of blood proteins is one factor in hemostasisby plasma treatment. Additionally, it was suggested that electrical property of the plasma
treatment is important for protein aggregation [2]. However, the detailed mechanism of theprotein aggregation is still not clear. This study aims to understand the mechanism of protein
aggregation by low-temperature atmospheric pressure plasma.
Plasma treatments were conducted using the setup as shown in Figure 1. The plasma wasproduced between a needle electrode and the surface of albumin solution by applying highvoltage. Albumin solution was used in the treatment because albumin is the most abundant
protein in blood. The plasma treatment results in aggregation of albumin as shown in the inset
in Figure 1. The growth process of aggregate was recorded and analyzed. Dependences of time
evolution of aggregate on plasma treatment conditions were investigated. The relationshipbetween the growth process and the conditions will be discussed in the conference.

Fig. 1: Experimental setup for protein aggregation. The inset shows the aggregate on thealbumin solution.
[1] References: H. Sakakita and Y. Ikehara, Plasma and Fusion Research 5, S2117 (2010).
[2] H. Sakakita, H. Yamada, T. Shimizu, M. Fujiwara, S. Kato, J. Kim, S. Ikehara, N. Shimizu,
and Y. Ikehara, J. Phys. D: Appl. Phys. 54, 215201 (2021).

P-38

Advances in Development of Quasi-axisymmetric Stellarator
at National Institute for Fusion Science
Mitsutaka Isobe1,2, Akihiro Shimizu1,2, Kunihiro Ogawa1,2, Hiromi Takahashi1,2,
Takanori Murase1, Hiroyuki Tanoue1, Sho Nakagawa1, Masaki Osakabe1,2,and Hiroyuki Yamaguchi1,21National Institute for Fusion Science, National Institutes of Natural Sciences
322-6, Oroshi, Toki, 509-5292, Japan
isobe.mitsutaka@nifs.ac.jp
2

The Graduate University for Advanced Studies, SOKENDAI
322-6, Oroshi, Toki, 509-5292, JapanA stellarator embedded with the magnetic symmetry of tokamak, hereafter quasiaxisymmetric stellarator (QAS), was proposed in the middle of 1990s [1,2], and is now
attracting attention again[3-6] since it will be disruption-free and is expected to provide plasma
confinement relevant to that of tokamaks while retaining steady-state operation capability.
The National Institute for Fusion Science (NIFS) has been developing QAS, i.e., netcurrent-free tokamak in both physics and engineering aspects since 1996. The first QAS in
NIFS was designed to be post-CHS, and was named CHS-qa. The toroidal period number (N)and major radius (R) of CHS-qa were 2 and 1.5 m, respectively. The target maximum toroidal
magnetic field strength (Bt) was 1.5 T. To be closer to aspect ratio (Ap) of tokamak, the CHSqa was designed to be low Ap of 3.2, following the policy of CHS. A primary purpose of CHSqa was to explore higher confinement regime of stellarator plasma through embedding
axisymmetry to 3-D torus and resulting reduction of non-axisymmetric magnetic field ripple.
The CHS-qa was not realized, and the design work was completed in 2004.
After many years, the opportunity to construct QAS came in 2017. NIFS and Southwest
Jiaotong University, China decided to implement a joint project together for design andconstruction of a new stellarator CFQS based upon a quasi-axisymmetry (QA) concept. The
CFQS has N of 2 like CHS-qa and R of 1 m, and is now under construction [7]. The first plasmaof CFQS will be achieved in 2024. To reduce technology challenges coming from strong
electromagnetic force, space availability, and manufacturability due to low Ap, we chose Ap of
4 and the maximum Bt of 1 T for the CFQS. The CFQS will be dedicated to proof-of-principle
experiment to prove intrinsic advantages of QAS with superior plasma diagnostics [8].
Lately significant progress has been made in QAS development at NIFS. We have found
QA configuration of which QA-ness is largely enhanced compared with that of CHS-qa and
CFQS. In this paper, progress of physics and engineering design for QAS at NIFS are presented.
[1] J. Nührenberg et al., in Theory of Fusion Plasmas (Proc. Joint Varenna-Lausanne Int.
Workshop Varenna, 1994), (Bologna:Editrice Compositori), p3 (1994).
[2] P.R. Garabedian, Phys. Plasmas 3 (1996) 2483.
[3] M. Isobe et al., Plasma Fus. Res. 14 (2019) 3402074.
[4] S.A. Henneberg et al., Nucl. Fusion 59 (2019) 026014.
[5] Z.Y. Lu et al., Nucl. Fusion 61 (2021) 106028.
[6] T. Qian et al., Nucl. Fusion 62 (2022) 084001.
[7] A. Shimizu et al., Nucl. Fusion 62 (2022) 016010.
[8] A. Shimizu et al., JINST 17 (2022) C06004.

P-39

Low-Temperature Sintering of Activated Carbon Using Spark Plasma
Sintering
Yuto YANAGIHARA1, Sho NAKAGAWA1, Takanori MURASE1, Kazuki NAGAHARA1,
Hiroyuki TANOUE1, Mitsutaka ISOBE1, 2, Kunihiro OGAWA1, 2, Akihiro SHIMIZU1, 2,
Hiroyuki NOTO1, Yuki HAYASHI1, 2, Pham Thi Huong Ngat3, Tomohiro SHIOZAKI3,
Toshiaki SOGABE3 and Mudtorlep Nisoa41

National Institute for Fusion Science, National Institutes of Natural Sciences
322-6, Oroshicho, Toki, 509-5292, Japanyanagihara.yuto@nifs.ac.jp
2

The Graduate University for Advanced Studies, SOKENDAI
322-6, Oroshicho, Toki, 509-5292, Japan
3

ANAORI CARBON Co., Ltd.
6-20, Hatakedacho, Ibaraki, Osaka, 567-0028, Japan
4

Functional Materials & Nanotechnology Center of Excellence, Walailak University
Nakhon Si Thammarat, 80160, Thailand

In the plasma experimental device at National Institute for Fusion Science, activated carbon
is utilized as an adsorbent within a cryopump to create the ultra-high vacuum environment
necessary for generating high-temperature plasma. The extensive porous structure of activatedcarbon is employed as a substrate in the cryopumps, adsorbing gas molecules, includinghydrogen, on its surface at cryogenic temperatures.
In this study, we aim to develop suitable activated carbon for cryopump applications.
Solidified activated carbon is necessary to mount it in a cryopump. Usually, activated carbon issolidified by mixing the activated carbon powder with a binder. However, the use of binders
obstructs the pores of the activated carbon, leading to a decline in its adsorption performance.
Thus, the focus shifts to the Spark Plasma Sintering (SPS) method, a technique involvingpressure and pulsed current heating to facilitate the sintering of activated carbon without binders.
800
700

Specific Surface Area [m 2/g]

600
500
400
300
200

Sintered
Condition of Activated Carbon

Before Sinteredo1600 Co

1400 Co1200 C

o

o

o

800 C

0

1000 C

100

650 C

Using the SPS technique, commercially available
activated carbon powder was sintered at six different
temperatures ranging from 650°C to 1600°C. As aresult, the activated carbons were successfully sinteredat every sintering temperature. Notably, as shown in
Fig. 1, the specific surface area of the activated carbon
exhibited an increase with lower temperature sintering.
Additionally, activated carbon sintered at temperatures
below 800°C displayed a greater specific surface area
compared to powdered activated carbon prior tosintering. Details will be reported in the presentation.

Fig. 1: Specific surface area ofactivated carbon at each sintering
temperature and prior to sintering.

P-40

Enhancement to gas puffing control system in LHD
Kazuki Nagahara, Hiromi Hayashi, Naoyuki Suzuki, Takanori Murase, Kohji Yasui,
Yasuyuki Tsuchibushi, Hiromi Kato, Masateru Kawai, Hidenori Takubo, Sho Nakagawa,Hiroki Chimura, Yuto Yanagihara
National Institute for Fusion Science, National Institutes of Natural Sciences,322-6 Oroshi-cho, Toki, Gifu 509-5292, Japannagahara.kazuki@nifs.ac.jp

In the Large Helical Device (LHD), the precise control of electron density is often required
according to the plasma experiment scenario. The electron density is controlled by supplying
the prescribed amount of fuel gas through the piezo valve. The previous gas puffing control
system was based on the feedback control of conventional proportional (P) control and required
several shots of plasma discharge to obtain the target electron density. To improve theperformance of electron density control, we have developed the feedback control system basedon proportional-integral (PI) control.
PI control is expressed by the following equation:
𝑉𝑐𝑡𝑟𝑙 = 𝐾𝑃 𝑒 + 𝐾𝐼 ∫ 𝑒𝑑𝑡,
where Vctrl, KP, e, and KI represent the control voltage of the piezo valve, the P gain, thedeviation of the current value from the target value of electron density, and the I gain,
respectively. P gain and I gain (PI gain) adjustment is essential for the proper PI control. PI gain
adjustment was performed during the actual plasma discharge. First, the initial value of the PI
gain was determined using the electron density signal simulated for that of far-infrared laserinterferometer by use of a function generator as a referential signal. PI control was performed
with the initial PI gain value, but the electron density oscillated unfavorably in this case. Next
the PI gain was adjusted to obtain the optimum value. As a result of applying the optimal value
for the PI gain, the target electron density could be obtained in almost all cases in a single shot.
The time evolutions of electron density with the initial value and the optimal value are shownin Fig. 1.
In addition to constant electron density control,
other density controls, e.g., ramp-up control, which
increases the density at a constant rate of change,and sinusoidal control, which makes the electron
density sinusoidal are required. With gainoptimized PI control, these controls could also beeasily implemented.
In this presentation, details of the gain
adjustment and examples of well controlled
various electron density will be presented.
Fig. 1: Time evolution of electron densitywith PI control with gain as the initialvalue (shot# 163827) and the optimalvalue (shot# 182450).

P-41

Surface observation on heat-treated activated carbon
derived from unutilized biomass
Sho NAKAGAWA1, Yuto YANAGIHARA1, Takanori MURASE1, Kazuki NAGAHARA1,
Hiroyuki TANOUE1, Mitsutaka ISOBE1,2, Kunihiro OGAWA1,2, Akihiro SHIMIZU1,2,
Hiroyuki NOTO1, Yuki HAYASHI1,2, Pham Thi Huong Ngat3, Tomohiro SHIOZAKI3,
Toshiaki SOGABE3, Mudtorlep Nisoa41

National Institute for Fusion Science, National Institutes of Natural Sciences
Toki, Gifu 509-5292, Japannakagawa.sho@nifs.ac.jp
2

The Graduate University for Advanced Studies, SOKENDAI
Toki, Gifu 509-5292, Japan
3
ANAORI CARBON Co., Ltd
Ibaraki, Osaka, 567-0028 Japan

4

Functional Materials &amp; Nanotechnology Center of Excellence, Walailak University,
Nakhon Si Thammarat, 80160, Thailand

The purpose of this research is to develop a functional activated carbon with outstanding
adsorption property using unutilized biomass as raw material. To achieve this goal, various
attempts have been made, such as vacuum heating for removing silica and Spark Plasma
Sintering (SPS) for binder-less solidification.
Microstructures and adsorption properties of prepared samples have been investigated. In
surface analysis with SEM-EDS, needle-like structure of silicon carbide (SiC), known as SiC
whisker, was observed on some samples. It is known that SiC whisker has excellent properties
such as high strength and high temperature resistance and can be used as reinforcement
composite material for metals and ceramics to improve their mechanical property.
Figure 1 shows image of SiC whiskers observed on a surface of biomass carbon, which issintered by SPS at 1600°C and 30 MPa. Figure 2 shows EDS elemental mapping of carbon andsilicon. It indicates a presence of Si on the whiskers in Fig. 1, which suggests that they are madeof SiC.
In this presentation, we will focus on SiC whiskers, and report on the differences in theirgrowing states depending on the treatment conditions and their potential application.
(a)Fig. 1: Image of SiC whiskers
observed on biomass carbon(b)Fig. 2: Images of EDS elemental mapping (a)of Carbon (b)and Silicon

P-42

Ferroptosis induced by plasma-activated Ringer’s lactate solution prevents
oral cancer progression

Kotaro Sato1,2,*, Ming Yang1,2, Kae Nakamura3, Hiromasa Tanaka3, Masaru Hori3, Miki
Nishio4, Akira Suzuki4, Hideharu Hibi1,3, Shinya Toyokuni2,3Department of Oral and Maxillofacial Surgery, Nagoya University Graduate School of Medicine,
65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japana1

b2

Department of Pathology and Biological Responses, Nagoya University Graduate School of Medicine,
65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
Center for Low-Temperature Plasma Sciences, Nagoya University,
Furo-cho, Chikusa-ku, Nagoya 464-8603, Japanc3

d4

Division of Molecular and Cellular Biology, Kobe University Graduate School of Medicine,
7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan

Objective: This study aimed to investigate the effect of plasma-activated Ringer’s lactate
solution (PAL) on oral squamous cell carcinoma (OSCC) cells and carcinogenic processes
with a particular focus on iron and collagenous matrix formation.
Materials and Methods: We used three OSCC cell lines, one keratinocyte cell line andtwo fibroblast lines, and cell viability assays, immunoblotting, flow cytometry andtransmission electron microscopy were performed to evaluate the effect and type of cell
death. The effect of PAL treatment on lysyl oxidase (LOX) expression was investigated invitro and in vivo. Tamoxifen-inducible Mob1a/b double-knockout mice were used for thein vivo experiment.
Results: PAL killed OSCC cells more effectively than control nontumorous cells andsuppressed cell migration and invasion. The type of cell death was ferroptosis, and theprotein level of LOX was down-regulated in cancer cells in vitro and in vivo. Additionally,
PAL improved the survival rate of mice and suppressed collagenous matrix formation.
Conclusions: We demonstrated that PAL specifically kills OSCC cells and thatferroptosis occurs in vitro and in vivo. Furthermore, PAL can prevent oral carcinogenesis
and improve the survival rate by changing collagenous matrix formation via LOX
suppression.

P-43

Plasma-activated solutions invigorate anti-tumor immune response in theintraperitoneal environments of ovarian cancer
Kae Nakamura1,2, Nobuhisa Yoshikawa1, Hiromasa Tanaka2,3, Kenji Ishikawa2
Masaaki Mizuno3, Shinya Toyokuni2,4, Masaru Hori2 and Hiroaki Kajiyama1,2
Department of Obstetrics and Gynecology, 3 Center for Advanced Medicine and Clinical Research,
Department of Pathology and Biological Responses, Nagoya University Graduate School of Medicine,
65 Tsurumai-Cho, Showa-ku, Nagoya, 466-8550, Japan
1

4

Center for Low-temperature Plasma Sciences
Furo, Chikusa, Nagoya 464-8603, Japank-naka@med.nagoya-u.ac.jp

2

Epithelial ovarian cancer (EOC) is the most lethal gynecologic malignancy. Due to its
asymptomatic progression, the majority of EOC patients are initially diagnosed at an advanced
stage, accompanied by peritoneal metastasis, and the current treatments yield unfavorable
prognoses for these patients. Peritoneal dissemination in EOC is recognized as an emblematic
pathological condition of refractoriness and therapeutic resistance. Within the intraperitoneal
tumor microenvironment, peritoneal mesothelial cells and other immune system cells transform
into cancer-associated cells, forming the foundation for refractory and treatment-resistantcharacteristics. Therefore, managing intraperitoneal dissemination in EOC represents a crucial
therapeutic approach.
As well as direct plasma, plasma-activated solutions have been proposed as a new
therapeutic tool for cancer treatment. Numerous studies have demonstrated the direct cytotoxic
effects of plasma-activated solutions on various cancer cells [1]. In our research, we showed
the effective inhibition of intraperitoneal metastasis in EOC mouse model using plasmaactivated medium (PAM) [2]. Further investigations illuminated that PAM evoked an immune
response, leading to the infiltration of M1-type macrophages at the dissemination site [3]. In
this study, we examined the effects of plasma-activated lactate Ringer's solution (PAL) on
immune cells, focusing mainly on the activation of T cells, which play a pivotal role in antitumor immunity.
Recent reports have proposed that the intra-abdominal environment of EOC patients ishighly immunosuppressed. Initial investigations have confirmed strong suppression of humanCD8 positive T cells by EOC patient-derived malignant ascites, implying the induction of
immunosuppression. Subsequently, we explored the potential of plasma-activated solutions tocancel this immune suppression. The results indicated that under optimal conditions, PAL could
reverse the immune suppression induced by ascites. This might provide the potential of aplasma-activated solution to exhibit efficacy not only on macrophages but also on other immune
cell types, suggesting a potential approach for cancer immunotherapy.
This work was partly supported in part by JSPS KAKENHI Grant Numbers 19H05462,
20K09640 and 23K08884 from the Ministry of Education, Culture, Sports, Science andTechnology of Japan.
[1] N. Yoshikawa, K. Nakamura, and H. Kajiyama, Free Radical Research, 57, 69 (2023).
[2] K. Nakamura, Y. Peng, F. Utsumi, H. Tanaka, M. Mizuno, S. Toyokuni, M. Hori, F.
Kikkawa and H. Kajiyama, Sci. Rep., 7, 6085 (2017).
[3] K. Nakamura, N. Yoshikawa, Y. Mizuno, M. Ito, H. Tanaka, M. Mizuno, S. Toyokuni, M.
Hori, F. Kikkawa, and H. Kajiyama, Cancers (Basel), 13, (2021).

P-44

Prevalence of antibiotic-resistant E. coli in wastewater treatment plant
effluent and the southern watershed of Lake Biwa
Chih-Yu Ma1
1
Louis Pasteur Center for Medical Research103-5 Tanaka Monzencho, Sakyo-ku, Kyoto, 606-8225, Japan
Takara1419@gmail.com

The overuse and imprudent use of antibiotic agents in agriculture, veterinary, and medical
sectors contribute significantly to the global epidemic increase in antimicrobial resistance(AMR). Wastewater treatment plants (WWTPs) are generally considered hotspots for the
dissemination of AMR into the aquatic environment because the biological treatment processes
applied in WWTPs cannot effectively remove both antibiotic-resistant bacteria (ARBs) and therelevant genes (ARGs).
In this study, we investigated the occurrence of antibiotic-resistant E. coli in the southernwatershed of Lake Biwa. A two-year monitoring of antibiotic-resistant E. coli was conductedin the southern part of Lake Biwa, inflow rivers, and at three WWTPs around the southern partof the lake. Concentrations of E. coli resistant to ampicillin (AMP), cefotaxime (CTX),
ceftazidime (CAZ), levofloxacin (LVFX), tetracycline (TC), and amikacin (AMK) were
measured using the culture method. Among these antibiotic-resistant E. coli, AMP-resistant E.
coli were found to be the most prevalent, followed by LVFX, CTX, CAZ, TC, and AMKresistant strains, both in the influent and effluent of WWTPs. These resistance patterns in
wastewater mirror those seen in clinical samples in Japan. The numbers of antibiotic-resistant
E. coli decreased by approximately a factor of 1000 during the wastewater treatment processes,
but the resistance ratio clearly increased, suggesting that the selection for antibiotic resistancemight occur during the wastewater treatment process. AMP-resistant and TC-resistant E. coli
were also detected in Lake Biwa and inflow rivers, suggesting that antibiotic resistance might
originate not only from WWTPs but also from livestock farms and small-scale wastewater
treatment facilities located in the river catchment.
Consequently, there is an urgent need to develop an efficient approach for the removal of
AMR in aquatic environments. The plasma-assisted advanced oxidation process, capable ofgenerating a large quantity of radicals and active species (including ·OH, O3, and H2O2), isgarnering increased attention as a novel method for water treatment and the removal of chemicaland biological pollutants from water. However, studies related to plasma in addressing the
AMR issue are still limited, and further research is necessary to evaluate its feasibility andutility.

P-45

Production of large volume plasma-activated water(PAW) for food andagricultural applications
D. Srinoum, S. Kaewpawong, Karaket Wattanasit and M. Nisoa

Plasmas and electromagnetic wave research laboratory,
Walailak University: 222 Taiburi, Tasala, Nakhon si thammarat, 80160, Thailand
mnisoa@gmail.com

Recently, plasma activated waters (PAW) have been investigatedintensively for sustainable agriculture and post-harvest technology. The waters
can be used effectively as green fertilizers, decontamination agent and green
pesticides, while no harmful by products left over[1-2]. The acidic characteristicsof the PAW, resulted from nitrate and hydrogen peroxide, can produce highgermination rate of various seeds[1,3]. In this work, PAW produced by RF cold
atmospheric plasma in moderated pressure will be presented. The plasma is
generated in closed chamber, whereas part of the chamber volume was filled withwater. The floating electrode, made of tungsten rod and inserted in the Pyrex glass
tube, is powered by RF power supply of 7 – 9 kV and 50 – 800 kHz. The plasmas,
generated above the water surface, for production of PAW. Various
characteristics of large volume PAW for the setup will be discussed.

1. L. Sivacha ndiran and A. Khacef, Enhanced seed germination and plant growthby atmospheric pressure cold air plasma: combined effect of seed and water
treatment, RSC Adv., 2017, 7, 1822–1832
2. Jin Shen and et.al., Bactericidal Effcts against S. aureus and Physicochemical
Properties of Plasma Activated Water stored at diffrent temperatures, Scientific
Reports, 6:28505, DOI: 10.1038/srep28505
3. S. Zhang , A. Ro ussea u and T. Dufour, Promoting lentil germination and stem
growth by plasma activated tap water, demineralized water and liquid fertilizer,
RSC Adv., 2017, 7, 31244–31251

P-46

Development of 10 kW helicon plasma source for material-plasmainteraction studies

S. Kaewpawong1, W. Kongsawat1, R. Taleh1, D. Srinoum1, A. Tamman2,
S. Dangtip2, Boonyarit Chatthong3 and M. Nisoa1

1

Plasmas and electromagnetic waves research laboratory, Walailak University: 222 Taiburi,
Tasala, Nakhon si thammarat, 80160, Thailand
mnisoa@gmail.com
2

Center of Excellence in Engineering and Nuclear Technology, Thailand Institute of Nuclear
Technology, Nakhon Nayok, 26120 Thailand
3
Division of Physical Science, Faculty of Science, Prince of Songkla University, Songkhla,
ThailandHigh-density linear plasma devices can produce plasmas similar to that of
the Tokamaks[1,2]. But they are simple and compact than the tokamaks. The
linear devices are much more cost-effective than the tokamaks for research on
plasma material interactions.
In this research, a linear helicon plasma device with permanent magnets
was fabricated. A half-turn helical antenna and 13.56 MHz RF were used to excite
helicon wave of m = +1. The 800 G magnetic field is uniform in the vicinity of
the antenna. Ar gas was used for the plasma discharges. The electron
temperatures and plasma densities were obtained by using optical emission
spectroscopy(OES) and Langmuir probe. When the helicon waves were excitedby RF power more than 400 W, high-density plasmas of more than 1013 cm−3
were obtained. The electron temperatures were in the ranges of 1 – 5 eV. The
linear helicon plasma device developed in work is excellence for the studies ofplasma material interaction (PMI) for development of fusion related materials.
The ion fluence, similar to that of the plasma-facing wall in tokamaks, can beinvestigated.

Reference[1] Caughman et al., Plasma source development for fusion-relevant material
testing, Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films
35, 03E114 (2017)[2] R. H Goulding et al., Progress in the Development of a High Power Helicon
Plasma Source for the Materials Plasma Exposure Experiment, Fusion Scienceand Technology, (2017)

P-47

Characteristics of high-power DC thermal plasmas for treatmentof medical wastes

R. Taleh, S. Kaewpawong, W. Kongsawat, D. Srinoum and M. Nisoa

Plasmas and electromagnetic wave research laboratory,
Walailak University: 222 Taiburi, Tasala, Nakhon si thammarat, 80160, Thailand
mnisoa@gmail.com

The 30 kW DC plasma torch system with the well-type cathode (WTC) has
been developed to generate thermal plasma above 1200 0C, which is adding theexternal magnetic coil on the cathodic part of the torch. The well-type torch ishollow cylindrical copper’s 5 mm thickness, whose cathode electrode and anodeelectrode was 150 mm in each length, the diameter is 22 mm through the center,
The gap between both electrodes is 1.5 mm isolated with a swirl gas ring.
Under the experimental conditions at 0.5 - 0.8 MPa compressed air isapplied to both sides of the torch, the airflow rate is 60 L/min and 120 L/min fromthe sides, and above, as followed. the thermal plasma has been generated, theirmaximum current is 200 A and 160 V, the length is about 30 cm, its diameter
about 3 to 5 cm wide, recognized UV emission has been present.
In this work, the 500 G of the magnetic field produced by an externalsolenoid has been developed, to drive the arc root and reduce the cathode erosion
damage. The result shows the necessity of a magnetic field, a rotational arc root
inside the cathode surface, and electrode life hours are compared with the case of
un magnetic field-driven has been present. Finally, the knowledge of this work toextend electrode life and applied to the system to be suitable for the disposal of
infectious wastes.

P-48

Atmospheric pressure hybrid plasma jet for oxygen atom generation
Akihiro Kajino1, Keigo Takeda1 and Mineo Hiramatsu1
1
Meijo University
1-501, Shiogamaguchi, Tempaku, Nagoya 468-8502, Japan
223427012@ccmailg.meijo-u.ac.jp

Application of non-equilibrium atmospheric pressure plasma (NEAPP) to biological field
has attracted because of its ability to produce reactive oxygen species (ROS) with highreactivity at low temperatures. It has been reported that the ROS such as ground state oxygen(O) atoms and ozone (O3) generated by the NEAPP inactivate various microorganisms [1]. The
O atom which is one of the important ROS is generated by the collisional dissociation ofmolecular oxygen (O2) with relatively high energy electron. On the other hand, the generationof O atom due to the electron collisional dissociation of O3 occurs at the lower electron energy
than the dissociation of O2 [2]. Therefore, the addition of O3 to the NEAPP discharge gas is
expected to increase the efficiency of O atom generation. In this study, the hybrid atmosphericpressure plasma jet (APPJ) apparatus has been constructed to supply O3 generated in dielectricbarrier discharge (DBD) plasma to an AC-excited APPJ (AC-APPJ) [3] in order to establish theefficient O generation method.
Figure 1 shows a schematic of the hybrid APPJ apparatus constructed in this study. N2 (5000
sccm) and air (500 sccm) were introduced into the quartz tube as discharge gas. And then, byapplying an AC high voltage to DBD electrode and AC-APPJ electrode, a DBD and the ACAPPJ were generated inside the quartz tube and near the exit port of gas jet, respectively. In
order to investigate the effect of the O3 supply timing on the generation of O atom in the ACAPPJ, the distance between the DBD and the AC-APPJ electrodes were set at 46, 56, 66, 76,
86, and 96 mm, and the emission intensity of O atoms in the AC-APPJ was observed at awavelength of 844 nm.
Figure 2 shows the optical emission intensity
ratios of O atom to N atom (observed 746 nm) for
the AC-excited APPJ at the distance of 46, 56, 66,
76, 86, and 96 nm between DBD and AC-APPJ
electrodes together with that of AC-APPJ without
DBD (No DBD). At 86 and 96 mm, the intensity
ratio was relatively higher than that at No DBD
condition. On the other hand, the intensity ratios at Fig. 1 Schematic of the hybrid APPJ.
46, 56, 66, and 76 mm were lower than that of No
DBD condition. This indicates that the O atom
generation was affected by the supply timing of O3.
From the result, it is considered the supply of O3 by
the hybrid plasma was effective in its generation.
[1] S. Iseki, et. al, Appl. Phys. Express 4, 116201(2011).
[2] M. Kuzumoto, et.al, JAPAN TAPPI JOURNAL
51, 2, 345 (1997).
[3] M. Iwasaki, et. al, Appl. Phys. Lett. 92,
081503 (2008).

Fig. 2 Optical emission intensity ratioof O (844 nm) to N atoms (746 nm) as
a function of the distance between
DBD and AC-APPJ electrodes.

P-49

Analysis of plasma flow velocity in highly collisional plasma jet by using
Mach probe for plasma aerosol deposition
In Je Kang*, Hyonu Chang, Soo Ouk Jang, Chang Hyun Cho, Ji Hun Kim, Hyun Jae Park,and Yong-Sup Choi
Institute of Plasma Technology, Korea Institute of Fusion Energy, Gunsan 54004, Republic of Korea
ijkang@kfe.re.kr

Experimental studies on plasma flow velocity under highly collisional plasma conditions
are insufficient with reliable results although the flow velocity is one of key parameters for theplasma aerosol deposition as the application of ceramic coating with plasma jet. In thispresentation, the parallel Mach probe was used to experimentally analyze the normalized
plasma flow velocity in a highly collisional plasma formed by a microwave plasma jet [1,2].
The velocity is a dimensionless unit which represents the plasma flow velocity relative to theion acoustic velocity. To estimate the plasma flow velocity under highly collisional plasma
conditions with 1 – 6 Torr, a collisional model of the Mach probe was proposed. Additionally,
the turbulent model was used to calculate the neutral gas flow velocity, which was assumed tobe the plasma flow velocity. The experimentally estimated results were found to be in good
agreement with a difference rate of 10 – 30% when compared to the results of the turbulent
model. After the optimization of conditions considering plasma flow velocity with the substrate
position, the Y2O3 coatings were deposited on an aluminum substrate. The thickness of thecoating layer was ~50 μm, with pore properties <10%.
This research was supported by the R&D Program of “Plasma Convergence andFundamental Research” (Grant No. EN2321-11) through the Korea Institute of Fusion Energy(KFE) funded by the Government funds, Republic of Korea.
[1] In Je Kang, Hyonu Chang, Yong-Sup Choi, Soo Ouk Jang, Chang Hyun Cho, Ji Hun Kim,
Hyun Jae Park, Curr. Appl. Phys., 39, 45 (2022).
[2] Kyu-Sun Chung, Plasma Sources Sci. Technol., 21, 063001 (2012).

P-50

Design on versatile large area PECVD system for the assessment of plasma
property
Hyunyeong Lee*, Kangil Lee, Young-Gi Kim, Daechul Kim, Jongsik Kim, Miyoung Song,and Yongsup Choi
Korea Institute of Fusion Energy
37 Dongjangsan-ro, Gunsan, Jeollabuk-do 54004, Republic of Korea
hylee@kfe.re.kr

Plasma processing including etching and deposition has an essential role for surface
treatment in semiconductor and display industry. Plasma processing for surface treatment has
an economic ripple effect and it is essential to identify the specifications and the assessment of
the plasma property for plasma processing. Therefore, the large area PECVD (Plasma Enhanced
Chemical Vapor Deposition) system for 300 mm wafer has been designed for versatile
experiments with assessment of plasma property. The CCP (Capacitively Coupled Plasma) type
PECVD has been designed for using 3 kW 13.56 MHz RF (Radio Frequency) power and will
be extended to 5 kW. In addition, OES (Optical Emission Spectroscopy) utilizing HR6 UVVIS spectrometer will be installed for diagnosing the processing plasma and experimental
condition. The detailed experiemental conditions of versatile larege area PECVD system will
be presented.

P-51

Etch characteristics of ITO using various hydrofluorocarbon gases
Jong Woo Hong1*, Dong Woo Kim1, Yu Gwang Jeong3, Hyun Min Cho3, Da Woon Jung3,
Yun Jong Yeo3, Geun Young Yeom1,2
1School of Advanced Materials Science and Engineering, Sungkyunkwan University
2066 Seobu-ro, Jangan-gu, Suwon-si, Gyeonggi-do, Republic of Korea
gyyeom@skku.edu

2

SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University
2066 Seobu-ro, Jangan-gu, Suwon-si, Gyeonggi-do, Republic of Korea
3

Process Research Team, Samsung Display
1, Samsung-ro, Giheung-gu, Yongin-si 17113, Gyeonggi-do, Republic of Korea

In this study, the etching characteristics of ITO were investigated using various hydrocarbon
gases mixed with Ar and examined the cleaning properties of etch residue with H2/Ar. The useof hydrofluorocarbon gases with a higher C/H ratio not only improved the etch rate of ITO but
also increased the etch selectivity over PR. This increase in etch selectivity can be attributed to
the reduced hydrogen content in the gas mixture, which not only enhances PR etching but also
minimizes damage to the PR material. The etching of ITO using various hydro mixed with Ar
appeared to involve the formation of compounds such as InCxHy, SnHx, SnCxHy, and COx on
the ITO surface, followed by the sputtering of these compounds by Ar+ ion bombardment.
Among the sputtered compounds, less volatile and adhesive compounds seemed to adhere to
the chamber walls, forming a polymer etch residue layer. This polymer layer could be
effectively removed using H2/Ar plasmas, leading to the formation of more volatile compounds
such as In(CH3)x (x=2,3), SnH4, and CH4.
[1] J. Lee, D. Kim, D. Yang, S. Hong, K. Yoon, P. Hong, C. Jeong, H. Park, S. Kim, S. Lim, S.
S. Kim, K. Son, T. Kim, J. Kwon, and S. Lee, SID Symposium Digest of Technical Papers, 39,
1 (2008).
[2] D.H. Kang, I. Kang, S.H. Ryu, and J. Jang, IEEE Electron Device Lett., 32, 10 (2011).
[3] S.W. Tsao, T.C. Chang, S.Y. Huang, M.C. Chen, S.C. Chen, C.T. Tsai, Y.J. Kuo, Y.C. Chen,
and W.C. Wu, Solid-State Electron., 54, 12 (2010).

P-52

Etching characteristics of SiON films with a low global warming potential
gas replacing CF4
Hyun Woo Tak1, Kim Seul Ki2, Seong Bae Kim1, Chan Hyuk Choi3, Dong Woo Kim1 andGeun Yong Yeom1,3
1School of Advanced Materials Science and Engineering, Sungkyunkwan University
2066 Seobu-ro, Jangan-gu, Suwon-si, Gyeonggi-do, Republic of Korea
gyyeom@skku.edu
2

Department of Semiconductor Display Engineering Sungkyunkwan University
2066 Seobu-ro, Jangan-gu, Suwon-si, Gyeonggi-do, Republic of Korea
3

SKKU Advanced Institute of Nano Technology (SAINT)
2066 Seobu-ro, Jangan-gu, Suwon-si, Gyeonggi-do, Republic of Korea

To fabricate semiconductor devices, dielectric etching is essential for creating nanoscale
devices with high integration circuits. As the integration level of semiconductor devices
increases, more etching steps and etching time are required, ultimately leading to the use oflarge quantities of fluorocarbon and hydrofluorocarbon gases. Commercial etch gases such as
CF4, CHF3, and C4F8 have high global warming potentials of 7380, 14600, and 10200,
respectively. This is a critical concern, especially in light of the recent statement from theUnited Nations in July 2023, warning of "The era of global warming."
Recent studies have actively explored the replacement of CHF3 and C4F8 with low Global
Warming Potential (GWP) gases, while meeting the requirements for improved etchingproperties in high aspect ratio contact structure etching using high-polymer-forming
fluorocarbons and hydrofluorocarbons. However, the replacement of CF4 has not been widely
investigated, as it possesses unique properties, with carbon bonded to four fluorine atoms. It isalso produced at a low cost and is chemically stable, making it relatively easy to understandits plasma dissociation properties, which result in intuitive etching behavior.
In this study, we propose a novel fluorocarbon base gas as a replacement for CF4 in SiON
etching, which is one of the essential steps required to form hardmasks, such as amorphous
carbon layers commonly used in various semiconductor manufacturing processes.
Additionally, we have designed the etching process with CH2F2, which has a relatively low
GWP value of 771 among hydrofluorocarbons. SiON etching also requires hydrogen to form
volatile HCN. Based on detailed etching results in SiON with nanoscale hole-patterned
photoresist, we can suggest that replacing CF4 with the novel gas and CH2F2 as an alternative
etching process in semiconductor manufacturing can effectively achieve the same (F-H)/(C-O)
ratio, offering an environmentally sustainable solution.
[1] H. S. Lee, K. C. Yang, S. G. Kim, Y. J. Shin, D. W. Suh, H. D. Song, N. E. Lee, and G. Y.
Yeom, J. Vac. Sci. Technol. A, 36, 061306 (2018).
[2] H. W. Tak, H. J. Lee, L. Wen, B. J. Kang, D. Sung, J. W. Bae, D. W. Kim, W. Lee, S. B.
Lee, K. Kim, B. O. Cho, Y. L. Kim, H. D. Song, and G. Y. Yeom, Appl. Surf. Sci., 600,
154050 (2022).
[3] H. J. Lee, H. W. Tak, S. B. Kim, S. K. Kim, T. H. Park, J. Y. Kim, D. Sung, W. Lee, S. B.
Lee, K. Kim, B. O. Cho, Y. L. Kim, K. C. Lee, D. W. Kim, and G. Y. Yeom, Appl. Surf. Sci.,
639, 158190 (2023).

P-53

Dependence of the film qualities on the solied densities of the targets
prepared by sputtering deposition with mixture powder targets
H. Kawasaki1, T. Satake1,2, T. Ohshima3, T. Kikuchi4, T. Sasaki4, A. Sugiura2, S. Aoqui21National Institute of Technology, Sasebo College, 1-1 Okishin, Sasebo, Ngasaki 857-1193, Japan
2
Sojo University, Ikeda, Nishi-ku, Kumamoto, 860-0082, Japan
3
Nagasaki University, I 1-14 Bunkyo, Nagasaki, Japan 852-8521, Japan
4
Nagaoka University of Technology, 1603-1, Kamitomioka Nagaoka, Niigata, 940-2188 , Japan

ITO (Sn doped In2O3), which has excellent electrical conductivity and transparency, is thecurrent mainstream transparent conductive film. However, indium, the raw material of ITO, isa rare metal and therefore expensive. As an alternative material to ITO, we focused on the
fabrication of AZO thin films by doping Al into ZnO, which is abundant in resources andinexpensive. However, it is hard to control metal doping ratio using conventional sputtering
deposition method, because high density bulk targets are generally used in the sputtering
deposition method. To prepare a thin film with certain element ingredients, we have beendeveloped new sputtering deposition method using powder targets. In this method, several kindof powders were mixed by mixer, and just put on the target holder in the vacuum chamber. And
then, thin films were deposited on the substrate which was set to the counter side. Therefore, itis easy to change doping density to control the target powder mixture. In this report, those Al
doped ZnO thin films were prepared using several types of Al and ZnO mixture powder targets.
We prepared the Al doped ZnO thin films by sputtering deposition using 4 kinds of targets,
which are 1) Unprocessed, 2) Heated to 150°C on target holder, 3) Pressurized at 15 MPa,4)Pressurized at 4.5t. Deposition rate of the film using sputtering deposition as a function of thepowder target condition, not shown here. Deposition rate using pressurized target are higher
than that of the un pressurized one. Figure 2 shows the XRD pattern of the prepared film using
sputtering deposition as a function of the powder target condition. All of the film shows
ZnO(002) peaks (2θ=34.4º). Peak intensities of the prepared film using pressurized target are
higher than that of the un pressurized one. These results suggest that Al and ZnO mixture
powder targets mixture thin films were successfully prepared on the Si and glass substrates
surface, and their deposition rate and crystralinity changed by solied density of the targets. This
study was supported in part by a Grant-in-Aid for Scientific Research in Priority Areas (A) (No.
18H03848) and (C) (No.23340181 and No.
16K04999), Grant for joint research between
National College of Technology and Nagaoka
University of Technology, Takahashi Industrial
and Economic Research Foundation and Nippon
FigureSheet Glass Foundation for Materials Scienceand Engineering[1] H. Kawasaki, H. Nishiguchi, T. Furutani, T.
Ohshima, Y. Yagyu, T. Ihara, M. Shinohara, Y.
Suda, Jpn. J. Appl. Phys. 57, 01AB02 (2018)[2] H. Nishiguchi, T. Ohshima, H. Kawasaki, T.
Fukuda, Jpn. J. Appl. Phys. 55, 01AF05(2016).
[3] H. Kawasaki, Y. Suda, T. Ohshima, Y. Yagyu,
M. Shinohara,and T. Ihara, Jpn. J. Appl. Phys
58, SAAD04 (2019).

Fig. 1 XRD pattern of the prepared filmusing sputtering deposition as a function of
the powder target condition.

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Introduction to IAEA coordinated research program (CRP):
AI for Fusion (AI4F)
Masayuki Yokoyama
National Institute for Fusion Science, Rokkasho Research Center,
2-166 Obuchi-Omotedate, Rokkasho, Aomori 039-3212, JapanThe IAEA (International Atomic Energy Agency) organized the Technical Meeting on
Artificial Intelligence (AI) for Nuclear Technology and Applications (#AI4Atoms) on 25–29
October 2021, to programmatically discuss to form the roadmap for IAEA role & support inuse of AI in nuclear science, technology, and applications. It consisted of 10 working groups(WGs) along with cross-cutting groups (enabling infrastructure, and advanced modelling andsimulation methodologies). There is a “Nuclear Fusion” WG (NFWG) in 10 WGs.
Prof. Hideo Nagatomo (Osaka University) and I (Masayuki Yokoyama) joined this NFWG
from Japan, to launch continuously discuss to form the Coordinated Research Project (CRP). It
resulted in the launch of CRP on AI for Accelerating Fusion R&D (2022–2027) with theobjective of accelerating fusion R&D with Machine Learning (ML)/AI, through the creation ofa platform and cross-community network for innovation and partnership.
(cf.,https://nucleus.iaea.org/sites/ai4atoms/ai4fusion/SitePages/What-is-AI-forFusion-.aspx?web=1)
This CRP is composed by four Work Packages (WP), as follows.
WP 1: Real-time MFE System Behaviour Prediction, Identification & Optimization Using
ML/AI Methods (MFE: Magnetic Fusion Energy)
WP 2: IFE Physics Understanding through Simulation, Theory and Experiment Using
ML/AI Methods (IFE: Inertial Fusion Energy)
WP 3: Feasibility of MFE and IFE Image Database
WP 4: Community Engagement & Workforce Development
The objectives, expected activities/output/outcomes for each WP are described on theabove-mentioned webpage.
This information was distributed via the mailing list of The Japan Society of Plasma Scienceand Nuclear Fusion Research in Japan, for calling the proposal from institutions/universities inJapan. Then, Osaka University and NIFS individually applied, and they were approved by the
IAEA.
The progress and on-going activities within this CRP framework, with emphasis on the
NIFS proposal entitled as Radiation collapse database (no disruptions) from LHD (Large
Helical Device), will be reported in the forum.