Plasma and Fusion Research
Volume 2, S1059 (2007)
Regular Articles
- Graduate School of Energy Science, Kyoto University, Uji 611-0011, Japan
- 1)
- Institute of Advanced Energy, Kyoto University, Uji 611-0011, Japan
- 2)
- Graduate School of Engineering, Osaka University, Suita 565-0871, Japan
- 3)
- High Temperature Plasma Center, The University of Tokyo, Kashiwa 277-8568, Japan
- 4)
- National Institute for Fusion Science, Toki 509-5292, Japan
- 5)
- Southwestern Institute of Physics, Chengdu 610041, China
Abstract
Characteristics of spontaneous transition to a high confinement mode (H-mode) have been studied in a helical-axis heliotron device, Heliotron J. The radiation profile measured with a silicon photodiode array shows that a interesting change in the profile occurs at the plasma edge region in the transition phase, forming a strong gradient near the last closed flux surface (LCFS). Relating to the transition, characteristics of bursty density and particle-flux fluctuations current in the scrape off layer (SOL) have been investigated. The probability distribution function for the fluctuations has a tail structure in the L-mode phase, while the tail is suppressed and its direction is reversed after the transition, which may be related to the suppression of edge-plasma turbulence.
Keywords
Heliotron J, H-mode transition, radiation profile, edge plasma turbulence, PDF
Full Text
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This paper may be cited as follows:
S. WATANABE, K. NAGASAKI, T. MIZUUCHI, S. KOBAYASHI, H. OKADA, K. KONDO, S. YAMAMOTO, Y. TORII, M. KANEKO, H. ARIMOTO, G. MOTOJIMA, Z. FENG, M. NOSAKU, T. TOMOKIYO, S. MATSUOKA and F. SANO, Plasma Fusion Res. 2, S1059 (2007).