Plasma and Fusion Research

Volume 14, 2401028 (2019)

Regular Articles


Observation of Potential Increase in the Central Cell due to ICRF Heating in the Non-Axisymmetric Anchor Cell on GAMMA 10/PDX
Atsuto TANAKA, Makoto ICHIMURA, Mafumi HIRATA, Ryuya IKEZOE1), Shuhei SUMIDA, Seowon JANG, Koki IZUMI, Yushi KUBOTA, Ryo SEKINE, Hiroki KAYANO, Mizuki SAKAMOTO and Yousuke NAKASHIMA
Plasma Research Center, University of Tsukuba, Tsukuba 305-8577, Japan
1)
Research Institute for Applied Mechanics, Kyushu University, Kasuga 816-8580, Japan
(Received 30 September 2018 / Accepted 21 December 2018 / Published 12 February 2019)

Abstract

We used the additional Ion Cyclotron Range of Frequency (ICRF) heating in the anchor cell for the high density plasma production. When the ICRF waves are excited with antennas installed in the anchor cell, it is observed that the plasma potential increases significantly and forms non-axisymmetric potential distribution in the periphery of the central cell. Experiments with different frequencies were carried out to understand the physical mechanism of this potential change due to the ICRF waves. It is confirmed that the ion heating does not play an important role to the potential increase. The floating potentials on some tips set outside of the plasma in the anchor cell remarkably decrease during the additional heating and non-axisymmetric distribution of the floating potential in the central cell depends on the antenna location in the anchor cell. It is suggested that the radial transport of electrons near the antennas in the non-axisymmetric anchor cells with the ICRF antennas is a possible candidate of the potential increase in the central cell.


Keywords

ICRF wave, anchor heating, potential, non-axisymmetric, GAMMA 10/PDX

DOI: 10.1585/pfr.14.2401028


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