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Bifurcation-Like Behavior of Electrostatic Potential in LHD

Akihiro SHIMIZU, Takeshi IDO, Masaki NISHIURA, Ryohei MAKINO¹⁾, Masayuki YOKOYAMA, Hiromi TAKAHASHI, Hiroe IGAMI, Yasuo YOSHIMURA, Shin KUBO, Takashi SHIMOZUMA, Naoki TAMURA and LHD Experiment Group

National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292, Japan

1)

Graduated School of Engineering, Nagoya University, Furo-cho, Chikusa, Nagoya 464-0814, Japan

(Received 10 December 2012 / Accepted 26 June 2013 / Published 26 September 2013)

Abstract

The temporal evolution of the potential is measured with the heavy ion beam probe (HIBP) in the Large Helical Device (LHD). A rapid change in the potential is observed early in the tangential neutral beam injection (NBI) phase, just after the switch from tangential to perpendicular NBI, and in a low-power electron cyclotron heated (ECH) discharge in the LHD. The radial profile of the potential is measured before and after the potential change. This rapid potential change is considered to indicate the bifurcation of the radial electric field in the edge region of the LHD plasma.

Copyright (c) 2013 The Japan Society of Plasma Science and Nuclear Fusion Research

Keywords

radial electric field, bifurcation, Heavy Ion Beam Probe, helical device

DOI: 10.1585/pfr.8.2402122

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This paper may be cited as follows:

Akihiro SHIMIZU, Takeshi IDO, Masaki NISHIURA, Ryohei MAKINO, Masayuki YOKOYAMA, Hiromi TAKAHASHI, Hiroe IGAMI, Yasuo YOSHIMURA, Shin KUBO, Takashi SHIMOZUMA, Naoki TAMURA and LHD Experiment Group, Plasma Fusion Res. 8, 2402122 (2013).