Thermal analysis and Ohmic loss estimation of polarizer for ITER ECCD system

国際熱核融合実験炉用電子サイクロトロン電流駆動装置の偏波器の熱解析と オーム損失の推定

三枝 幹雄*; 高橋 幸司; 柏 吉忠*; 大石 晋平*; 星 勇気*; 中畑 裕行*; 春日井 敦; 坂本 慶司; 今井 剛*

Saigusa, Mikio*; Takahashi, Koji; Kashiwa, Yoshinori*; Oishi, Shimpei*; Hoshi, Yuki*; Nakahata, Hiroyuki*; Kasugai, Atsushi; Sakamoto, Keishi; Imai, Tsuyoshi*

国際熱核融合実験炉用電子サイクロトロン電流駆動装置の偏波器を開発し、170GHz, 441kW, 6sまでの大電力長パルス試験を行った。また、偏波器へ入力する直線偏波の入射偏波面を別の偏波器で回転させて偏波器の損失を温度上昇で測定したところ、偏波器の高周波損失は、入射偏波と回折格子の回転角に大きく依存し、その依存性は電磁界解析結果と定性的に一致した。電子サイクロトロン波のプラズマへの高効率結合に必要な入射偏波条件における損失の変化範囲は、理論値で0.2%から1.6%程度にまで変化した。

The specification of an electron cyclotron current driving (ECCD) system in International Thermonuclear Experimental Reactor (ITER) demands severe operational conditions for transmission lines and polarizers. For evaluating Ohmic loss of a miter bend type polarizer, the six polarizers were made of chromium copper alloy, installed in miter bends and tested at a frequency of 170GHz, rf power of 441kW and pulse duration of 0.1-6 seconds. The increase in temperature on the back of the grooved mirrors has been measured with thermo couplers during high power rf pulses. The Ohmic loss of grooved mirrors strongly depends on the rotation angle of the polarization plane of the incident waves and the mirror rotation in high power experiments, for example the Ohmic loss distributed from 0.2% to1.6%. The thermal analysis of grooved mirror has been performed with the 3D FEM code: FEVA. The all strange behavior of Ohmic loss of polarizers could be explained, theoretically.