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YOUNIS Jawad, WAN Baonian, LIN Shiyao, SHI Yuejiang, and HT-7 Team

HT-7

Study of LHW current drive efficiency and

fast electron distribution function

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Motivations Compare the experimental FEB spectra with simulation Investigate the dependence of photon temperature on loop voltage

with fixed plasma parameters. Investigate the dependence of photon temperature on plasma

parameters To get the precise HXR profile data. Reach LHW current drive efficiency with zero loop voltage even

negative loop voltage. Investigate the dependence of photon temperature on loop voltage

with different plasma parameters. Study the relation between photon

temperature and the fast electron distribution function.

HT-7

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Plasma parameters

HT-7

Ip＝ 80-200 kA

ne＝ 0.5- 3.0*1019m-3

LHW power scan from 60 to 500kW in steps

LHW phase velocity scan: n//=1.8, 2.35, 2.9, 3.45

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HT-7

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HT-7

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HT-7

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HT-7

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HT-7

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HT-7

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SummaryIn summary, dependence of Tph on plasma parameters is investigated

experimentally. The photon temperature increases with increasing plasma current at constant LH power and plasma density due to increased loop voltage. Due to the stronger slow down process at higher density, the Tph decreases with

increasing plasma density at constant LH power and plasma current although the loop voltage increased. In LH wave phase scan and power scan experiments, no appreciable change in the Tph is observed. The asymmetry in

the distribution function describes the driven current and estimates the photon temperature by two parameters, one is cutoff energy and the other is fast electron population. The results in current, density and phase scan experiment are quantitatively in good agreement with the simulation results.

The maximum CD efficiency is found to be 2.5 E19 .The full CD and over CD is obtained with low plasma parameters.

HT-7

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Thanks for attention