Experimental Study on Slowing-Down Mechanism of Locked-Mode-Like Instability in LHD

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Author(s)

    • TAKEMURA Yuki
    • National Institute for Fusion Science, National Institutes of Natural Sciences|SOKENDAI (the Graduate University for Advanced Studies)
    • YOSHINUMA Mikiro
    • National Institute for Fusion Science, National Institutes of Natural Sciences|SOKENDAI (the Graduate University for Advanced Studies)
    • TSUCHIYA Hayato
    • National Institute for Fusion Science, National Institutes of Natural Sciences
    • YAMADA Ichihiro
    • National Institute for Fusion Science, National Institutes of Natural Sciences
    • WATANABE Kiyomasa
    • National Institute for Fusion Science, National Institutes of Natural Sciences
    • TOKUZAWA Tokihiko
    • National Institute for Fusion Science, National Institutes of Natural Sciences
    • SAKAKIBARA Satoru
    • National Institute for Fusion Science, National Institutes of Natural Sciences|SOKENDAI (the Graduate University for Advanced Studies)
    • NARUSHIMA Yoshiro
    • National Institute for Fusion Science, National Institutes of Natural Sciences|SOKENDAI (the Graduate University for Advanced Studies)
    • OHDACHI Satoshi
    • National Institute for Fusion Science, National Institutes of Natural Sciences|SOKENDAI (the Graduate University for Advanced Studies)
    • SUZUKI Yasuhiro
    • National Institute for Fusion Science, National Institutes of Natural Sciences|SOKENDAI (the Graduate University for Advanced Studies)
    • IDA Katsumi
    • National Institute for Fusion Science, National Institutes of Natural Sciences|SOKENDAI (the Graduate University for Advanced Studies)

Abstract

<p>In order to clarify the mechanism responsible for slowing down the precursor of an instability in Large Helical Device (LHD), whose behavior is similar to the locked mode instability in tokamaks, the spatial structure of the precursor of the locked-mode-like instability, and the relationship between the rotation of the precursor and the <b>E </b>× <b>B </b>rotation were experimentally investigated. The precursor rotates together with the <b>E </b>× <b>B </b>rotation at the resonant surface, and the precursor rotation slows down because of a decrease of the <b>E </b>× <b>B </b>rotation. The multi-channel fluctuation measurement of the precursor suggests that the precursor has a magnetic island, which may be related to the decrease of the <b>E </b>× <b>B </b>rotation. In addition, the reason for the appearance of the precursor with a magnetic island is discussed. The precursor appears when a magnetic island grows initially without rotation but then shrinks and begins to rotate.</p>

Journal

  • Plasma and Fusion Research

    Plasma and Fusion Research 12(0), 1402028-1402028, 2017

    The Japan Society of Plasma Science and Nuclear Fusion Research

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