(SG3) Instability & Anisotropy group report
Date: May. 28, 2024
Time: 10:25 – 16:45
Shot#: 192009 – 192122 (114 shots)
Prior wall conditioning: Yes (H2)Divertor pump: Yes
Gas puff: H2, Ar, CH4May. 29, 2024 (T. Kawate)

NBI#(1, 2, 3, 4, 5)=gas(H, H, H, H, H)=P(4.4, 3.6, 3.9, 2.9, 4.2)MWECH(77GHz)=ant(5.5-U, 2-OUR)=P(0.70, 0.38)MWECH(154GHz)=ant(2-OLL, 2-OUL, 2-OLR)=P(0.71, 0.81, 0.98)MWICH(3.5U, 3.5L, 4.5U, 4.5L)=P(-, -, -, -)MWTopics
1. Measurement of fluctuation of electron velocity distribution function from high harmonics
electron cyclotron emission (E. Kawamori (National Cheng Kung Univ.), H. Igami)
2. Direct observation of bulk phase space dynamics during the energetic particle driven
Geodesic Acoustic Mode (Y. Kawachi (Nagoya Univ.), T. Kobayashi)
3. Manipulation of radial electric field using perpendicular neutral beam injection for improved
confinement (Z. Lin (UCI), M. Osakabe)Measurement of electron entropy (velocity distributionfunction) from high harmonic ECE

Kawamori E. (National Cheng Kung Univ. Taiwan), Igami H., Tokuzawa T. (NIFS)

Shot #: 192009-192064
Magnetic configuration: (Rax, Polarity, Bt, γ, Bq) = (3.60, CW, 1.0, 1.2538, 100),

Background and motivation:• Entropy(− ∫ $#! ln($#! ))*) transport is a key for understanding turbulent heat transport• Validation of our idea of $#! * measurement from harmonics of ECE

Method:• Observe ECE from optically thin plasmas, whose fe(v) is externally perturbed by
NB/ECH modulation• Crosscheck of $#! * measurement by ECE with Thomson scattering measurement
Result:• Fluctuation of high harmonic ECE induced by ECH modulation was confirmed• Further investigation including comparison with Thomson scattering measurement will beconductedECE power [V]Electron heating power was modulated in
optically thin plasmas#192060

0.3
0.2

56GHz ECH (50 Hz modulation)

0.1
0
3.7

3Ωce ECE@R~4.3 m (60.5GHz)
3.9time [s]4.1• Fluctuation of 3rd harmonics ECE
driven by ECH modulation wasobserved• Low ne plasmas were produced by NB start-up• Te (measured by Thomson scatt.) fluctuation by
ECH modulation was observed• Comparison b/w ECE & Thomson
scattering measurement results is to beconductedDirect observation of bulk phase space dynamics during the energetic particle driven Geodesic Acoustic ModeY. Kawachi et al

Shot #: 192069-192102 (total 36 shots)Experimental conditions: (Rax, Polarity, Bt , γ, Bq ) = (3.75 m, CW, 1.375 T, 1.2538, 100 %)Objective: Investigation how the EGAM affects the ion temperature by using Fast CXSThanks forT. Kobayashi

What we did:••

We investigated low density and the EGAM excitation
condition even when the NB#5 was injection
we measured the velocity distribution dynamics by using
12 channels of Fast CXS with 10kHz sampling

Results:- We successfully found the EGAM excitation condition
with NB#5 50ms on/off modulation operation- EGAM like chirping signal and bursty mode exhibiting
NB5on

second harmonics of GAM frequency with n=0!!

characteristics

Future work:- We will analyze Fast CXS data to investigate velocity
distribution dynamics, and HIBP data to examineinternal structure of the observed modes

NB5off

2nd harmonics of GAM

chirping EGAM

< 0.5 ×10"#Thanks forT. Ido

n=0Motivation: Manipulation of radial electric field throughneutral beam injection
Two sets of scans
1.

2.

Scan 3 injection energies of NB5 by 3
different parallel beam arrangements(copassing, counterpassing, mixed) for a
total of 9 shots.
Scan the fraction of beam power goingfrom perpendicular to parallel. All shotsin this scan will have a total injection
power of 6 MW.

All shots will have ECH on for half of the shot
to measure the effects in both electron root
and ion root

Future work: Perform simulations tocompare Er growth with experiment,
and compare Er between all shots

3.6 m, 2.75 T, clockwise magnetic field fromabove, HIBP potential measurements,~half of the shots were quiescent

Energy Scan

NB5
4 sources
25 keV
3 sources
30 keV
2 sources
40 keV

NB1:H
NB3:H

NB1: H
NB2: HNB2:F

Power scan
6 MW Perp
0 MW Parallel
NBI 5: F
NBI 4: F
Mixed

4.5 MW Perp
1.5 MW Parallel
NBI 5: F
NBI 4: H

0 ParallelCounter passing

Copassing

3 MW Perp
3 MW Parallel
NBI 5: F
NBI 4: 0

1.5 MW Perp
4.5 MW Parallel
NBI 5: H
NBI 4: 0

NB1: H
NB2: H
NB1: H
NB3: 0

NB1: H
NB3: H0 MW Perp
6 MW Parallel
NBI 5: 0
NBI 4: 0
NB1: F
NB2: F

NB1: H
NB3: F

NB2: F

Note that NBI 4 is always used for diagnostic purposes