Plasma and Fusion Research
Volume 3, S1077 (2008)
Regular Articles
- National Institute for Fusion Science, Toki, Gifu 509-5292, Japan
- 1)
- Research Institute for Applied Mechanics, Kyushu University, Fukuoka 816-8580, Japan
- 2)
- Fusion Research Development Division, Japan Atomic Energy Agency, Naka 311-0193, Japan
- 3)
- Faculty of engineering, Tohoku University, Sendai 980-8579, Japan
- 4)
- Graduate school of Energy Science, Kyoto University, Kyoto 606-8501, Japan
Abstract
An active current drive is a promising technique for improving plasma performances by controlling rotational transform and/or magnetic shear profiles in helical devices. A current drive based on electron cyclotron resonance heating is the most appropriate scheme for this purpose in terms of locality of driven current. Optimum conditions for an efficient electron cyclotron current drive (ECCD) in Large Helical Device (LHD) are being investigated using three-dimensional ray-tracing code, which can simulate propagation and power dissipation of electron cyclotron waves with large parallel refractive index. In the present experiment, inversion of directions of driven plasma current corresponding to injected ECCD modes was demonstrated successfully, and the results could be elucidated by the Fisch-Boozer theory. In addition, clear shifts of rotational transform were observed by motional Stark effect polarimetry. Our findings verified that the ECCD can be used as an effective actuator for controlling the rotational transform and magnetic shear profile in LHD.
Keywords
electron cyclotron current drive, magnetic shear control, rotational transform control, motional stark effect, large helical device
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This paper may be cited as follows:
Takashi NOTAKE, Takashi SHIMOZUMA, Shin KUBO, Hiroshi IDEI, Katsumi IDA, Kiyomasa WATANABE, Satoru SAKAKIBARA, Taiki YAMAGUCHI, Mikirou YOSHINUMA, Takashi KOBUCHI, Shigeru INAGAKI, Tokihiko TOKUZAWA, Yasuo YOSHIMURA, Hiroe IGAMI, Tetsuo SEKI, Hitoshi TANAKA, Kazunobu NAGASAKI and LHD Experimental Group, Plasma Fusion Res. 3, S1077 (2008).