(IA) Instability and Anisotropy group report
Date: May. 22, 2024
Time: 10:30 - 16:45
Shot#: 191641 –191767 ( 127 shots)

May 23, 2024 (R. Seki)

Prior wall conditioning: OFF
Divertor pump: off
Gas puff: He, Pellet: B, SiB6
NBI#(1, 2, 3, 4, 5)=gas(H, H, H, H, H)=P(4.0,3.8,4.1,3.4,4.5)MWECH(56GHz)=ant(1.5-U)=P(-.-)MW
ECH(77GHz)=ant(5.5-U, 2-OUR)=P(0.698, 0.38)MWECH(154GHz)=ant(2-OLL, 2-OUL, 2O-LR)=P(0.705, 0.889, 0.982)MWICH(3.5U, 3.5L, 4.5U, 4.5L) = P(0.6, 0, 0.62, 0)MWTopics
1. Study of the fast-ion acceleration by ICRF heating for p-11B fusion reaction. (R. Magee, M.Osakabe)
2. Validation of improved p-11B fusion reactivity using MeV ICRF tail ions in LHD. (J. Wang)
3. Dependence of p-11B fusion reactivity on the boron density profile and fast ion confinement time. (Y. Fujiwara,M. Osakabe)1Study of fast-ion acceleration by ICRF heating with p-11B fusion reaction(R. Magee, J. Wang, K. Ogawa, H. Gota, R. Seki., S. Kamio, M. Isobe, M. Osakabe et al.)Shot #:191649-1917691 (42 shots)Experimental conditions: (Rax, Polarity, Bt, γ, Bq) = (3.60 m, CCW, 2.75 T, 1.254, 100%)

Executive Summary:-1.0
0 2 4 6 8 10t (s)

-0.5

0.0

100.5

15 MHz low pass filter added to collection electronics (★)
allow PIPS detector to operate during ICRH pulses

signal (V)•Study of fast-ion acceleration by ICRF heating with p-11B fusion reaction(R. Magee, J. Wang, K. Ogawa, H. Gota, R. Seki., S. Kamio, M. Isobe, M. Osakabe et al.)Shot #:191649-1917691 (42 shots)Experimental conditions: (Rax, Polarity, Bt, γ, Bq) = (3.60 m, CCW, 2.75 T, 1.254, 100%)••

15 MHz low pass filter added to collection electronics (★)
allow PIPS detector to operate during ICRH pulses
Performed plasma density, boron density, and beam energy
scans
ICRH impact on fusion reactivity is small, requires careful data
analysis

ICRH on (191674)
ICRH off (191675)

1005002250

count rate (kcps)•count rate (kcps)

Executive Summary:15046t (s)8106t (s)810ICRH on (191667)
ICRH off (191669)

20015010050024

Study of fast-ion acceleration by ICRF heating with p-11B fusion reaction(R. Magee, J. Wang, K. Ogawa, H. Gota, R. Seki., S. Kamio, M. Isobe, M. Osakabe et al.)Shot #:191649-1917691 (42 shots)Experimental conditions: (Rax, Polarity, Bt, γ, Bq) = (3.60 m, CCW, 2.75 T, 1.254, 100%)

Executive Summary:•15 MHz low pass filter added to collection electronics (★)
allow PIPS detector to operate during ICRH pulses
Performed plasma density, boron density, and beam energyscans•

ICRH impact on fusion reactivity is small, requires careful dataanalysis•

Effect is observed most clearly during ICRH modulation

200
count rate (kcps)

•150
100
50
0
5.5

6.0

6.5

7.0t (s)

7.5

8.0

8.5

Validation of improved p-11B fusion reactivity using MeV ICRF tail ions in LHD(J. Wang, R. Magee, K. Ogawa, H. Gota, R. Seki., S. Kamio, M. Isobe, M. Osakabe et al.)Shot #:191692-191728 (37 shots)Experimental conditions: (Rax, Polarity, Bt, γ, Bq) = (3.60 m, CCW, 2.75 T, 1.254, 100%)
Background and motivation:•

In the previous campaigns, n-NBI induced p-11B fusion has been successfully measured in LHD.

•

It has also been identified in previous campaigns that ICRF wave can effectively accelerate particles to the MeV-energy range.

•We perform the p-11B experiment with an ICRF wave accelerated minority hydrogen/beam hydrogen tail in LHD under a standard ICRF heating scenario. A higher count rate on thefusion-born alphas is expected by the superposition of ICH to n-NBI.

Results:•[Left panel] ICRF-induced p-11B fusion is successfully identified. A higher Alpha-particle-induced PIPS counting rate is achieved in the absence of modulated NB4.

•

[Left panel] Superposition of ECH (77GHz, 2O-UR, ~0.4MW) to the ICH decreases the PIPS counting rate. We will check the boron behavior by ECH.

•

[Right panel] Enhanced PIPS counting rate is observed by the superposition of ICH to the half-power n-NBI.

•[Right panel] Superposition of ECH (77GHz, 2O-UR, ~0.4MW) to the ICH-NBI synergy slightly increases the PIPS counting rate. Contrary to the minority ion heating.

1MW ICRF
without n-NBI

1MW ICRF+2MW n-NBI

Solid: PIPS
Dashed: H ratio

Solid: PIPS
Dashed: H ratio

ECH ends @8s

ECH ends @8s

Dependence of p-11B fusion reactivity on the boron density profile and fast ion confinement time
(Y. Fujiwara, S. Kamio, R. Magee, H. Gota, K. Ogawa, N. Tamura, et al.,)Shot #:191729-191767 (39 shots)Experimental conditions: (Rax, Polarity, Bt, γ, Bq) = (3.60 m, CCW, 2.75 T, 1.254, 100%)
Background and motivation:•Building upon the success of the previous experimental campaigns that observed alpha particles resulting from proton-boron (p-11B) fusion reactions induced by NBI, we aim for an efficient alphaparticle generation condition.

•The purpose of this proposal is to investigate the relationship between the boron ion density profile in high-temperature plasma and the alpha particle production rate with NBI heating by comparing
discharges with boron powder and boron pellet injection.

Results:•

We have successfully detected alpha particle emission rate in three different boron injection experiments that were using B pellet, B TESPEL, and SiB6 TESPEL.

•

In that order, the alpha particle emission rates were more significant for B pellet, B TESPEL, and SiB6 TESPEL.

•The alpha particle emission decay was faster for B pellet than for TESPEL.

•Future analysis will include boron density distribution and fast ion distribution in plasma.

B pellet injection

B TESPEL injection

SN191732 boron pellet injection
9-O

SiB6 TESPEL injection

Alpha particle emission decay