Plasma and Fusion Research
Online ISSN : 1880-6821
ISSN-L : 1880-6821
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High Harmonic ECH Experiment for Extension of Heating Parameter Regime in LHD
Takashi SHIMOZUMAHiromi TAKAHASHIShin KUBOYasuo YOSHIMURAHiroe IGAMIMasaki NISHIURAShinya OGASAWARARyohei MAKINOHiroshi IDEINikolai B MARUSHCHENKOYuri TURKINTakashi MUTOH
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2013 Volume 8 Pages 2402073

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Abstract

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.

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© 2013 by The Japan Society of Plasma Science and Nuclear Fusion Research
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