Plasma and Fusion Research

Volume 3, 026 (2008)

Letters

Electron Cyclotron Heating Start-Up Experiments on TST-2

Junichi SUGIYAMA, Akira EJIRI, Yuichi TAKASE, Osamu WATANABE²⁾, Yuuki ADACHI, Hiroshi TOJO, Makoto SASAKI¹⁾, Tetsuya MASUDA, Takuya OOSAKO and Soichiro KAINAGA¹⁾

Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa 277-8561, Japan
1): Graduate School of Science, The University of Tokyo, Bunkyo 113-0033, Japan
2): High Temperature Plasma Center, The University of Tokyo, Kashiwa 277-8561, Japan

(Received 7 January 2008 / Accepted 7 April 2008 / Published 28 May 2008)

Abstract

Experiments were performed to study non-inductive current generation by electron cyclotron heating (ECH) in the TST-2 spherical tokamak. A magnetron (2.45 GHz/5 kW) and a horn antenna were used to inject either the O- or X-mode. The maximum plasma current does not depend on the injected wave polarization; however, it has a weak dependence on the vertical field configuration and is proportional to the vertical field. The initial current ramp-up rate depends on various operational parameters. The ramp-up rate increases with the injected EC wave power, and decreases with the filling pressure, resonance position (i.e., the toroidal field strength), and vertical field strength. It also depends on the magnetic field configuration. Conversely, the ramp-up rate does not depend on wave polarization, suggesting that multiple pass absorption of the EC wave is important.

Keywords

spherical tokamak, electron cyclotron heating, current drive, plasma start-up

DOI: 10.1585/pfr.3.026

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This paper may be cited as follows:

Junichi SUGIYAMA, Akira EJIRI, Yuichi TAKASE, Osamu WATANABE, Yuuki ADACHI, Hiroshi TOJO, Makoto SASAKI, Tetsuya MASUDA, Takuya OOSAKO and Soichiro KAINAGA, Plasma Fusion Res. 3, 026 (2008).