Configuration Control Studies in Heliotron J

Journal Article · Mon Apr 07 04:00:00 EDT 2008 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.2917021· OSTI ID:21137030

Mizuuchi, T; Kobayashi, S; Okada, H; Nagasaki, K; Hanatani, K; Sano, F ^[1]; Yamamoto, S ^[2]; Motojima, G; Watanabe, S; Arimoto, H; Murai, K; Hamagami, F; Katayama, D; Matsuoka, H; Nakajima, A; Takahashi, H; Yasuda, H; Mukai, K; Matsuyama, A; Kowada, Y ^[3]

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1. Institute of Advanced Energy, Kyoto University, Gokasho, Uji 611-0011 (Japan)
2. Kyoto University Pioneering Research Unit for Next Generation, Gokasho, Uji 611-0011 (Japan)
3. Graduate School of Energy Science, Kyoto University, Gokasho, Uji, 611-0011 (Japan)

Heliotron J is a flexible concept exploration facility for the helical-axis heliotron concept. One of the major objectives of the Heliotron J study is to experimentally confirm the effects of the new ideas introduced into this concept to improve the plasma performance. As a part of such experiments, the bumpiness ({epsilon}{sub b}) and rotational transform ({iota}/2{pi}) control studies have been performed. The {epsilon}{sub b}-control experiments have revealed the {epsilon}{sub b}-dependence of the fast ion confinement is qualitatively consistent with the drift optimization viewpoint. However, the bulk plasma confinement studies suggest that the low effective helical ripple configuration seems to be preferable for the confinement improvement for ECH-only plasma. The {iota}/2{pi}-control experiments for ECH-only and/or ECH+NBI plasmas have revealed the existence of windows in the vacuum {iota}(a)/2{pi} for the high quality H-mode. In NBI-only plasmas, it was found out that the transition in NBI-only plasma occurs at a certain toroidal current, which depends on the vacuum {iota}(a)/2{pi} and the bumpiness but is independent of P{sub inj}. This suggests the relation of the onset of the transition to the modification of the rotational transform caused by the plasma current.

• OSTI ID: 21137030
• Journal Information: AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 996; ISSN APCPCS; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
BEAM INJECTION HEATING
CONFIGURATION CONTROL
ECR HEATING
ELECTRIC CURRENTS
H-MODE PLASMA CONFINEMENT
HELIOTRON
IONS
NEUTRAL ATOM BEAM INJECTION
OPTIMIZATION
PERFORMANCE
PLASMA
ROTATIONAL TRANSFORM
STELLARATORS
TURBULENCE