Plasma and Fusion Research

Volume 13, 1402124 (2018)

Regular Articles

Effect of Electron Cyclotron Current Drive on the Ion Temperature in the Plasma Core Region of the Large Helical Device
Yasuo YOSHIMURA1), Akira EJIRI2), Ryosuke SEKI1), Ryuichi SAKAMOTO1,3), Kenichi NAGAOKA1,4), Takashi SHIMOZUMA1), Hiroe IGAMI1), Hiromi TAKAHASHI1,3), Toru I. TSUJIMURA1), Felix WARMER5), Kota YANAGIHARA4), Yuki GOTO4), Katsumi IDA1,3), Mikiro YOSHINUMA1,3), Tatsuya KOBAYASHI1,3), Shin KUBO1,4), Masaki OSAKABE1,3), Tomohiro MORISAKI1,3) and the LHD Experiment Group
1)
National Institute for Fusion Science, National Institutes of Natural Sciences, Toki, Gifu 509-5292, Japan
2)
The University of Tokyo, Graduate School of Frontier Sciences, Kashiwa, Chiba 277-8561, Japan
3)
SOKENDAI (The Graduate University for Advanced Studies), Department of Fusion Science, Toki, Gifu 509-5292, Japan
4)
Nagoya University, Graduate School of Engineering, Nagoya, Aichi 464-8603, Japan
5)
Max Planck Institute for Plasma Physics, EURATOM Association, D-17491 Greifswald, Germany
(Received 12 December 2017 / Accepted 29 October 2018 / Published 20 December 2018)

Abstract

An indirect effect of the electron cyclotron current drive (ECCD) on the ion temperature in the plasma core region was observed in the Large Helical Device. The reference (no ECCD) discharge with a central ion temperature Ti0 of ∼3.0 keV is operated by a standard high ion temperature discharge procedure. To investigate the ECCD effect, a co- or counter-ECCD was applied to the reference discharge, and was turned off immediately before the Ti0 peaked in the reference discharge. In the co-ECCD and counter-ECCD applications, the Ti0 temporarily increased and decreased by ∼0.5 keV from Ti0 in the reference discharge, respectively. The mechanism of this phenomenon is presently unclear, but may be exploited as a practical knob for controlling the central ion temperature.

Keywords

electron cyclotron current drive (ECCD), ion temperature, Large Helical Device (LHD)

DOI: 10.1585/pfr.13.1402124

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