2015 Annual Meeting of The Institute of Electrostatics JapanTokyo Metropolitan University
September 24-25, 2015

24pA-1
September 24th (Thu.), <15:45-17:45>
Room 1

Effect of Discharge Conditions on Inception Electric Field
Strength of Streamer in Water
〇Takehiko SATO*, Hidemasa FUJITA**, Seiji KANAZAWA***, Kiyonobu
OHTANI*, Atsuki KOMIYA* and Toshiro KANEKO*****,**,**** Tohoku University, ***Oita University

Abstract:
Effects of gap distance, capacitance, and water conductivity on theinception electric field strength of a primary streamer and a secondary streamer
in water were investigated in the case of a single-shot pulsed positive voltage
with a duration of 10 ?s. It was clarified that the inception electric field strength
was not effected by discharge conditions, and threshold electric field streangthfor the inceptions of a primary streamer is greater than 23 MV/cm and and forthat of a secondary streamer is greater than 34 MV/cm.

2015 Annual Meeting of The Institute of Electrostatics JapanTokyo Metropolitan University
September 24-25, 2015

24pA-2September 24th (Thu.), <15:45-17:45>
Room 1

Influence of Conductivity on DC Negative Corona Discharge
from a Water Droplet
Takuya Nakajima
Graduated School of Science and Engineering, Yamagata University

Abstract:
DC corona discharge from a water droplet formed at a capillary electrodeis accompanied with periodical formation and disruption of a Taylor cone.
Thus, corona discharge from a water droplet occurs intermittently withregular interval. Formation of a cone and charge transfer in a droplet might berelated to ion mobility in a droplet. In this study, to confirm the influence of theconductivity of a water droplet on the negative corona discharge, the magnitude
of corona current and the time variation of the droplet height were investigated.
Conductivity of a water droplet was adjusted by a concentration of HNO3 from
0.48 to 48mS/cm. The higher conductivity of a droplet, the larger corona current
flows. However, the conductivity affects little the cone formation of a waterdroplet. It takes more time for a larger water droplet to return to the lower
position of droplet. As a result, pulse trains corona discharge continues with arelatively longer duration.

2015 Annual Meeting of The Institute of Electrostatics JapanTokyo Metropolitan University
September 24-25, 201524pA-3
September 24th (Thu.), <15:45-17:45>
Room 1

Basic Experiment of Rod-to-Water Electrode Discharge
Using Inverter Neon Transformer〇Naoya HAYASHI, Itaru FUJITA, Sayo OKUDA, Toru HARIGAI, Yoshiyuki
SUDA, Hirofumi TAKIKAWA
Toyohashi University of Technology

Abstract:
There are nitrate ions as nutrients necessary for the growth of plants.
Nitrate ions can be generated in water by discharge. In this study, rod-to-water
discharge experiment that places the ground electrode in the water waspresented using an inverter neon transformer.
Unstable discharge appeared immediately at the beginning of discharge.
After the discharge for 30 s, discharge was stable. The pH and nitrate ion
concentration in water after discharge was increased with increasing ofdischarge duration.

2015 Annual Meeting of The Institute of Electrostatics JapanTokyo Metropolitan University
September 24-25, 2015

24pA-4September 24th (Thu.), <15:45-17:45>
Room 1Analysis of compositions of the ions generated byatmospheric pressure helium plasma〇Kenkichi NAGATO, Mizuki ASAE and Takahito SETO
National Institute of Technology, Kochi College

Abstract:
Chemical compositions of the ions generated by atmospheric pressure
helium plasma were investigated using an atmospheric pressure ionization mass
spectrometry (API-MS). The plasma generator used in this experiment wascomposed by a union-tee, a quartz glass tube and a stainless steel rod. In thenegative ion mass spectrum with a distance between the glass tube tip and thesampling orifice being 5 mm, several ion species were observed. The observed
ions include O－, OH－, O2－, O3－, CO3－, HCO3－ and HCO4－. Most ofthese ions formed hydrated cluster ions and the ions of O2－(H2O)n were themost abundant in the spectrum. The spectrum changed significantly by changing
the distance between the glass tube tip and the sampling orifice to 10 mm. The
peak of CO3－ became the most intense peak and the ions of O2－and HCO4－ decline, which was probably due to the ion-molecule reactions withsurrounding molecules.

2015 Annual Meeting of The Institute of Electrostatics JapanTokyo Metropolitan University
September 24-25, 2015

24pA-5September 24th (Thu.), <15:45-17:45>
Room 1

Observation of streamer discharge under high temperatures〇Taku KAMAKURA and Ryo ONO
The Univ. of TokyoAbstract:
Observation of streamer discharge under high temperatures Departmentof Advanced Energy, The University of Tokyo Kamakura Taku Pulsed positive
streamer discharge in a point-to-plane gap is observed under high temperatures(300-1200 K) and compared with various applied voltages (12-30 kV). An ICCD
camera is used for the optical measurements of streamer. The rises intemperature and applied voltage increase the reduced electric field E/n. The
results show that the rises in temperature and applied voltage increase thepropagation velocity of primary streamer and the length of secondary streamerin similar ways, while they lead to different shape of streamer (thickness,branching, etc.).

2015 Annual Meeting of The Institute of Electrostatics JapanTokyo Metropolitan University
September 24-25, 2015

24pA-6
September 24th (Thu.), <15:45-17:45>
Room 1

Generation and Characterization of Mist-Plasma Using
Atmospheric Pressure Glow Discharge○Tomoyuki TANAKA
Graduate School of Science and Engineering, Tokyo Metropolitan University

Abstract:
In this study we constructed mist-plasma experimental system using theatmospheric pressure DC glow discharge. We carried out the characterization ofthe mist-plasma by the measurements of optical emission spectroscopy anddroplet diameter.