[Table of Contents]

Plasma and Fusion Research

Volume 6, 1202131 (2011)

Rapid Communications

Magnetic Helicity Injection Mechanism for Double-Null Startup of the UTST Spherical Tokamak Plasmas
Takenori G WATANABE, Yasushi ONO, Takuma YAMADA, Shuji KAMIO, Qinghong CAO, Naoto SUZUKI, Koji ISHIGUCHI1) and Michiaki INOMOTO
Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa 277-8561, Japan
1)
The Open University of Japan, Mihama 261-8586, Japan
(Received 29 May 2011 / Accepted 25 July 2011 / Published 12 September 2011)

Abstract

A close relationship between magnetic helicity injection and magnetic reconnection was observed during double-null formation of spherical tokamak (ST) plasmas. The magnetic reconnection of common flux into private flux causes concentration of current density along the current sheet, forming a high eigen-value area between the helicity source (coil flux) and the ST plasma. The formation of a plasmoid and its translation to core plasma indicate intermittent translation of the high eigen-value area, suggesting a mechanism for helicity injection.

Keywords

spherical tokamak, helicity, plasmoid, magnetic reconnection, current sheet

DOI: 10.1585/pfr.6.1202131

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This paper may be cited as follows:

Takenori G WATANABE, Yasushi ONO, Takuma YAMADA, Shuji KAMIO, Qinghong CAO, Naoto SUZUKI, Koji ISHIGUCHI and Michiaki INOMOTO, Plasma Fusion Res. 6, 1202131 (2011).