[Table of Contents]

Plasma and Fusion Research

Volume 8, 2402118 (2013)

Regular Articles

Non-Inductive Current Drive by EC Waves in an Inboard Poloidal Magnetic Field Null Configuration on the Spherical Tokamak QUEST
Saya TASHIMA1), Hideki ZUSHI2), Mitsutaka ISOBE3), Hiroshi IDEI2), Shoichi OKAMURA3), Kazuaki HANADA2), Kazuo NAKAMURA2), Akihide FUJISAWA2), Keisuke MATSUOKA2), Makoto HASEGAWA2), Yoshihiko NAGASHIMA2), Shoji KAWASAKI2), Hisatoshi NAKASHIMA2), Aki HIGASHIJIMA2) and QUEST Team
1)
IGSES, Kyushu University, Kasuga, Fukuoka 816-8580, Japan
2)
RIAM, Kyushu University, Kasuga, Fukuoka 816-8580, Japan
3)
National Institute for Fusion Science, Toki 509-5292, Japan
(Received 21 November 2012 / Accepted 18 June 2013 / Published 26 September 2013)

Abstract

To investigate the effects of confinement of fast electrons on poloidal beta equilibrium, experiments under different toroidal magnetic mirror ratios, MOMFC, were performed in electron cyclotron heated plasma in the spherical tokamak QUEST. The proportional constants of the relation between plasma current and vertical magnetic fields decreased with increase in MOMFC. The poloidal field null point appeared in the chamber for MOMFC > 1.8 at a plasma current value of ∼15 kA. Poloidal beta and temperature of hard X-rays increased with MOMFC. This suggests that high poloidal beta equilibrium plasma is produced by better confinement of energetic trapped particles.

Keywords

non-inductive current drive, electron cyclotron resonance heating, energetic electron, high poloidal beta, trapped electron

DOI: 10.1585/pfr.8.2402118

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This paper may be cited as follows:

Saya TASHIMA, Hideki ZUSHI, Mitsutaka ISOBE, Hiroshi IDEI, Shoichi OKAMURA, Kazuaki HANADA, Kazuo NAKAMURA, Akihide FUJISAWA, Keisuke MATSUOKA, Makoto HASEGAWA, Yoshihiko NAGASHIMA, Shoji KAWASAKI, Hisatoshi NAKASHIMA, Aki HIGASHIJIMA and QUEST Team, Plasma Fusion Res. 8, 2402118 (2013).