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Optimization of Incident EC Wave Polarization in Real-Time Polarization Scan Experiments on LHD

Toru I. TSUJIMURA¹⁾, Yoshinori MIZUNO¹⁾, Ryohei MAKINO¹⁾, Shin KUBO¹⁾, Hiroe IGAMI¹⁾, Takashi SHIMOZUMA¹⁾, Yasuo YOSHIMURA¹⁾, Hiromi TAKAHASHI^1,2), Hiroshi KASAHARA^1,2), Sakuji KOBAYASHI¹⁾, Satoshi ITO¹⁾, Kota OKADA¹⁾, Takashi MUTOH^1,2) and the LHD Experiment Group¹⁾

1)National Institute for Fusion Science, Toki 509-5292, Japan

2)SOKENDAI (The Graduate University for Advanced Studies), Toki 509-5292, Japan

(Received 27 November 2015 / Accepted 11 January 2016 / Published 4 March 2016)

Abstract

Real-time polarization scan experiments were performed on the Large Helical Device (LHD) to search an optimal incident wave polarization for electron cyclotron resonance heating. The obtained optimal polarization state to maximize the power absorption to the LHD plasma is compared with the ray-tracing code that includes mode content analyses, which indicates that the calculated results are generally in good agreement with the experimental results. The analyses show that optimal coupling to plasma waves requires a fine adjustment for an incident wave polarization even for perpendicular injection due to the finite density profile and the magnetic shear at the peripheral region.

Copyright (c) 2016 The Japan Society of Plasma Science and Nuclear Fusion Research

Keywords

electron cyclotron resonance heating, incident wave polarization, ray-tracing code, mode content analysis, large helical device

DOI: 10.1585/pfr.11.2402016

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