Plasma and Fusion Research

Volume 2, S1065 (2007)

Regular Articles

Soft X-ray Emission Profile and Mode Structure During MHD Events in the TST-2 Spherical Tokamak

H. TOJO, A. EJIRI, Y. TAKASE, Y. TORII, T. OSAKO, M. SASAKI¹⁾, T. MASUDA, Y. SHIMADA, N. SUMITOMO¹⁾, J. TSUJIMURA, H. NUGA¹⁾, S. KAINAGA¹⁾ and J. SUGIYAMA

Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa 277-8561, Japan
1): Graduate School of Science, The University of Tokyo, Tokyo 113-0033, Japan

(Received 4 December 2006 / Accepted 20 April 2007 / Published 20 November 2007)

Abstract

Mode structures during MHD events in the TST-2 spherical tokamak are revealed by means of singular value decomposition. Soft X-ray and magnetic coil signals show growths of modes with toroidal mode numbers n = 1 and 2. Slow evolution of the soft X-ray profile indicates beginning of localized crash. Occurrence of these events is correlated with the spatial gradient of the soft X-ray profile, suggesting that these events are driven by the pressure gradient. Increases in impurity ion temperatures (CIII and OV) are observed. These are positively correlated with the increment of the plasma current during these events.

Keywords

IRE, spherical tokamak, SVD, soft X-ray, ion temperature, reconnection

DOI: 10.1585/pfr.2.S1065

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References

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This paper may be cited as follows:

H. TOJO, A. EJIRI, Y. TAKASE, Y. TORII, T. OSAKO, M. SASAKI, T. MASUDA, Y. SHIMADA, N. SUMITOMO, J. TSUJIMURA, H. NUGA, S. KAINAGA and J. SUGIYAMA, Plasma Fusion Res. 2, S1065 (2007).