ICRF-Induced Changes in Floating Potential and Ion Saturation Current in the EAST Divertor
1 Princeton Plasma Physics Laboratory, Princeton, New Jersey, U.S.A
2 Institute for Plasma Physics, Chinese Academy of Science, Hefei, China
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Published online: 23 October 2017
Injection of waves in the ion cyclotron range of frequencies (ICRF) into a tokamak can potentially raise the plasma potential via RF rectification. Probes are affected both by changes in plasma potential and also by RF-averaging of the probe characteristic, with the latter tending to drop the floating potential. We present the effect of ICRF heating on divertor Langmuir probes in the EAST experiment. Over a scan of the outer gap, probes connected to the antennas have increases in floating potential with ICRF, but probes in between the outer-vessel strike point and flux surface tangent to the antenna have decreased floating potential. This behaviour is investigated using field-line mapping. Preliminary results show that mdiplane gas puffing can suppress the strong influence of ICRF on the probes’ floating potential.
© The authors, published by EDP Sciences, 2017
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