https://doi.org/10.1051/epjconf/201715703039
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
* e-mail: rperkins@pppl.gov
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
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
