High harmonic ECH experiment for extension of heating parameter regime in LHD

Takashi Shimozuma, Hiromi Takahashi, Shin Kubo, Yasuo Yoshimura, Hiroe Igami, Masaki Nishiura, Shinya Ogasawara, Ryohei Makino, Hiroshi Idei, Nikolai B. Marushchenko, Yuri Turkin, Takashi Mutoh

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    3 Citations (Scopus)


    High harmonic electron cyclotron resonance heating (ECH) can extend the plasma heating region to higher density and higher β compared to the normal heating scenario. In this study, the heating characteristics of the second-harmonic ordinary (O2) and third-harmonic extraordinary (X3) modes and the possible extension of heating regime are experimentally confirmed. At the same time, a comparative study using ray-tracing calculation was performed in the realistic three-dimensional configuration of the Large Helical Device. The O2 mode heating showed a 40% absorption rate even above the X2 mode cut-off density. The X3 mode heating using powerful 77 GHz gyrotrons demonstrated an increase of about 40% in the central electron temperature in the plasmas at β-value of about 1%. These results were quantitatively explained to some extent by ray-tracing calculations.

    Original languageEnglish
    Article number2402073
    JournalPlasma and Fusion Research
    Publication statusPublished - 2013

    All Science Journal Classification (ASJC) codes

    • Condensed Matter Physics


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