Plasma and Fusion Research

Volume 8, 1403039 (2013)

Regular Articles

Formation of Electron-Root Radial Electric Field and its Effect on Thermal Transport in LHD High T_e Plasma

Seikichi MATSUOKA, Shinsuke SATAKE, Hiromi TAKAHASHI, Arimitsu WAKASA¹⁾, Masayuki YOKOYAMA, Takeshi IDO, Akihiro SHIMIZU, Takashi SHIMOZUMA, Sadayoshi MURAKAMI¹⁾ and LHD Experiment Group

: National Institute for Fusion Science, Toki 509-5292, Japan
1): Department of Nuclear Engineering, Kyoto University, Kyoto 606-8501, Japan

(Received 17 July 2012 / Accepted 5 March 2013 / Published 22 May 2013)

Abstract

Neoclassical transport analyses have been performed for a high electron temperature LHD plasma with steep temperature gradient using a neoclassical transport simulation code, FORTEC-3D. It is shown that the large positive radial electric field is spontaneously formed at the core along with the increase in the electron temperature, while the neoclassical heat diffusivity remains almost unchanged. This indicates that the 1/ν-type increase expected in the neoclassical transport in helical plasmas can be avoided by the spontaneous formation of the radial electric field. At the same time, it is found that the experimentally estimated heat diffusivity is significantly reduced. This suggests that the formation process of the transport barrier in the high electron temperature plasma can be caused by the spontaneous formation of the radial electric field.

Keywords

radial electric field, finite orbit width effect, neoclassical transport, δf Monte Carlo simulation

DOI: 10.1585/pfr.8.1403039

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This paper may be cited as follows:

Seikichi MATSUOKA, Shinsuke SATAKE, Hiromi TAKAHASHI, Arimitsu WAKASA, Masayuki YOKOYAMA, Takeshi IDO, Akihiro SHIMIZU, Takashi SHIMOZUMA, Sadayoshi MURAKAMI and LHD Experiment Group, Plasma Fusion Res. 8, 1403039 (2013).