[Table of Contents]

Plasma and Fusion Research

Volume 2, S1080 (2007)

Regular Articles


Change of Edge Plasma Distribution during a Discharge in Heliotron J
Tohru MIZUUCHI, Zhen FENG1), Nobuhiro NISHINO2), Kazunobu NAGASAKI, Hiroyuki OKADA, Shinji KOBAYASHI, Hajime ARIMOTO3), Gen MOTOJIMA3), Shinya WATANABE3), Satoshi MATSUOKA3), Masatoshi NOSAKU3), Takashi TOMOKIYO3), Nobuyuki WATANABE3), Katsumi KONDO3) and Fumimichi SANO
Institute of Advanced Energy, Kyoto Univ., Gokasho, Uji 611-0011, Japan
1)
Southwestern Institute of Physics, Chengdu 610041, China
2)
Graduate School of Engineering, Hiroshima Univ., Higashi-Hiroshima 739-8527, Japan
3)
Graduate School of Energy Science, Kyoto Univ., Gokasho, Uji 611-0011, Japan
(Received 4 December 2006 / Accepted 27 February 2007 / Published 20 November 2007)

Abstract

In order to monitor the diverted plasma flux distribution for various field configurations in Heliotron J, a new edge-plasma monitor system was installed. During a single discharge, a high-speed video camera (250-500 fps) records a stack of two-dimensional images of visible light emission (mainly from recycling neutrals) near a movable carbon target, which is inserted to the peripheral region of the core plasma. A spontaneous shift of the brightest spot of the light emission along the target was clearly observed. This shift is qualitatively consistent with a poloidal shift of the diverted plasma position which was observed in the diverted plasma flux measurement with a Langmuir probe-array near the wall at a different toroidal position. These findings indicate the global shift of the edge plasma position during a discharge. The most plausible mechanism for the observed shift is the change of the edge field topology caused by a non-inductive plasma current of a few kA.


Keywords

divertor plasma distribution, edge-field topology, non-inductive current, two-dimensional imaging technique, Heliotron J, helical-axis heliotron, low magnetic shear

DOI: 10.1585/pfr.2.S1080


References

  • [1] F. Wagner et al., 19th IAEA FEC (Lyon, 2002), OV2-4.
  • [2] F. Sano et al., Nucl. Fusion 45, 1557 (2005).
  • [3] F. Sano et al., J. Plasma and Fusion Res. SERIES 3, 26 (2000).
  • [4] T. Obiki et al., Nucl. Fusion 41, 833 (2001).
  • [5] T. Mizuuchi et al., J. Plasma and Fusion Res. SERIES 3, 192 (2000).
  • [6] T. Mizuuchi et al., J. Nucl. Mater. 313-316, 947 (2003).
  • [7] N. Nishino et al., J. Nucl Mater. 337-339, 1073 (2005).
  • [8] H. Shidara et al., Fusion Sci. Technol. 45, 41 (2004).
  • [9] S. Kobayashi et al., 20th IAEA FEC, (Vilamoura, Portugal, Nov. 2004), IAEA-CN-116/EX/P4-41.

This paper may be cited as follows:

Tohru MIZUUCHI, Zhen FENG, Nobuhiro NISHINO, Kazunobu NAGASAKI, Hiroyuki OKADA, Shinji KOBAYASHI, Hajime ARIMOTO, Gen MOTOJIMA, Shinya WATANABE, Satoshi MATSUOKA, Masatoshi NOSAKU, Takashi TOMOKIYO, Nobuyuki WATANABE, Katsumi KONDO and Fumimichi SANO, Plasma Fusion Res. 2, S1080 (2007).