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Configuration Effects on Local Transport in High-Beta LHD Plasmas

Hisamichi FUNABA, Kiyomasa WATANABE, Sadayoshi MURAKAMI¹⁾, Satoru SAKAKIBARA, Hiroshi YAMADA, Kazumichi NARIHARA, Ichihiro YAMADA, Kenji TANAKA, Tokihiko TOKUZAWA, Masaki OSAKABE, Junichi MIYAZAWA, Masayuki YOKOYAMA, Kazuo KAWAHATA and the LHD Experimental Group

National Institute for Fusion Science, Toki, Gifu 509-5292, Japan

1)

Department of Nuclear Engineering, Kyoto University, Kyoto 606-8501, Japan

(Received 4 September 2007 / Accepted 25 February 2008 / Published 19 May 2008)

Abstract

To distinguish between the beta effect and configuration effect due to an increment in beta on the gradual degradation of the global confinement property in high-beta plasmas on the Large Helical Device (LHD), the local transport characteristics in the high-beta plasmas are studied by considering the change in the major radius of the magnetic flux surface with the beta value. First, the influence of the change in the magnetic configuration on the local transport is studied in low-beta plasmas, and it is confirmed that the dependence of the local transport properties on the magnetic configuration is almost the same as that proposed in the ISS04 scaling in the entire plasma region. Next, the dependence of the local transport characteristics in high-beta plasmas on the major radial position of a geometric center of the magnetic flux surface is studied in comparison with that in low-beta plasmas. The dependence of the local transport in the peripheral region is correlated more with beta itself than the magnetic configuration effect, whereas the core transport appears to be correlated more with the configuration effect.

Copyright (c) 2008 The Japan Society of Plasma Science and Nuclear Fusion Research

Keywords

high beta plasma, magnetic configuration, global confinement, local transport, international Stellarator/Heliotron scaling

DOI: 10.1585/pfr.3.022

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This paper may be cited as follows:

Hisamichi FUNABA, Kiyomasa WATANABE, Sadayoshi MURAKAMI, Satoru SAKAKIBARA, Hiroshi YAMADA, Kazumichi NARIHARA, Ichihiro YAMADA, Kenji TANAKA, Tokihiko TOKUZAWA, Masaki OSAKABE, Junichi MIYAZAWA, Masayuki YOKOYAMA, Kazuo KAWAHATA and the LHD Experimental Group, Plasma Fusion Res. 3, 022 (2008).