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 ISHIGUCHI; Michiaki INOMOTO

doi:10.1585/pfr.6.1202131

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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 ISHIGUCHI, Michiaki INOMOTO

Author information

Takenori G WATANABE
Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa 277-8561, Japan
Yasushi ONO
Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa 277-8561, Japan
Takuma YAMADA
Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa 277-8561, Japan
Shuji KAMIO
Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa 277-8561, Japan
Qinghong CAO
Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa 277-8561, Japan
Naoto SUZUKI
Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa 277-8561, Japan
Koji ISHIGUCHI
The Open University of Japan, Mihama 261-8586, Japan
Michiaki INOMOTO
Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa 277-8561, Japan

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

JOURNAL FREE ACCESS

2011 Volume 6 Pages 1202131

DOI https://doi.org/10.1585/pfr.6.1202131

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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.

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