Plasma and Fusion Research

Volume 2, S1056 (2007)

Regular Articles

High-Speed Visible Imaging of the Central-Cell Plasmas in the GAMMA 10 Tandem Mirror

Yousuke NAKASHIMA, Nobuhiro NISHINO¹⁾, Yuta HIGASHIZONO, Hirokazu KAWANO, Shinji KOBAYASHI²⁾, Mamoru SHOJI³⁾, Yuusuke KUBOTA, Takayuki KOBAYASHI, Masayuki YOSHIKAWA, Hiroyuki HIGAKI, Md. Khairu ISLAM, Yoshiyuki MISHIMA and Teruji CHO

Plasma Research Center, University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan
1): Graduate school of Engineering, Hiroshima University, Hiroshima 739-8527, Japan
2): Institute of Advanced Energy, Kyoto University, Gokasho, Uji 611-0011, Japan
3): National Institute for Fusion Science, Toki, Gifu 509-5292, Japan

(Received 7 December 2006 / Accepted 26 April 2007 / Published 20 November 2007)

Abstract

Details of two-dimensional imaging performed in the central-cell of the GAMMA 10 tandem mirror by using high-speed camera are described. At the GAMMA 10 central-cell midplane, a high-speed camera (MEMRECAM fx-K4, NAC Inc.) was mounted and the shape and the motion of plasmas were precisely investigated. In the standard ion cyclotron range of frequency (ICRF) heated plasmas, gas puffing of hydrogen with short pulse (3-5 ms) close to the central-cell midplane was carried out to illuminate the periphery plasma and the time evolution of visible light emitted from the gas was captured. The Hα line-emission was localized close to the port of gas puffer. In the pellet injection experiments, 2-D images of the ablation light induced by hydrogen ice-pellet injection were successfully captured at the GAMMA 10 central-cell. Analysis of 2-D images clarified that the electron cyclotron heating applied in the central-cell (c-ECH) has a significant influence on the edge plasma turbulence and the ablation of hydrogen ice-pellet.

Keywords

GAMMA 10, tandem mirror, high-speed camera, two-dimensional image, plasma turbulence, gas puff imaging, pellet injection

DOI: 10.1585/pfr.2.S1056

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This paper may be cited as follows:

Yousuke NAKASHIMA, Nobuhiro NISHINO, Yuta HIGASHIZONO, Hirokazu KAWANO, Shinji KOBAYASHI, Mamoru SHOJI, Yuusuke KUBOTA, Takayuki KOBAYASHI, Masayuki YOSHIKAWA, Hiroyuki HIGAKI, Md. Khairu ISLAM, Yoshiyuki MISHIMA and Teruji CHO, Plasma Fusion Res. 2, S1056 (2007).