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Author(s):
K. Saito, R. Kumazawa, T. Mutoh, T. Seki, T. Watari, Y. Torii, D.A. Hartmann, Y. Zhao, A. Fukuyama, F. Shimpo, G. Nomura, M. Yokota, M. Sasao, M. Isobe, M. Osakabe, T. Ozaki, K. Narihara, Y. Nagayama, S. Inagaki, K. Itoh, S. Morita, A.V. Krasilnikov, K. Ohkubo, M. Sato, S. Kubo, T. Shimozuma, H. Idei, Y. Yoshimura, O. Kaneko, Y. Takeiri, Y. Oka, K. Tsumori, K. Ikeda, A. Komori, H. Yamada, H. Funaba, K.Y. Watanabe, S. Sakakibara, M. Shoji, R. Sakamoto, J. Miyazawa, K. Tanaka, B.J. Peterson, N. Ashikawa, S. Murakami, T. Minami, S. Ohakachi, S. Yamamoto, S. Kado, H. Sasao, H. Suzuki, K. Kawahata, P. deVries, M. Emoto, H. Nakanishi, T. Kobuchi, N. Inoue, N. Ohyabu, Y. Nakamura, S. Masuzaki, S. Muto, K. Sato, T. Morisaki, M. Yokoyama, T. Watanabe, M. Goto, I. Yamada, K. Ida T. Tokuzawa, , N. Noda, S. Yamaguchi, K. Akaishi, A. Sagara, K. Toi, K. Nishimura, K. Yamazaki, S. Sudo Y. Hamada, O. Motojima, M. Fujiwara
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Title:
Ion and Electron Heating in ICRF Heating Experiments on LHD
Date of publication:
Mar. 2001
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Key words:
ICRF heating, ion heating, electron heating, heating efficiency, helical system, LHD
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Abstract:
This paper reports on the Ion Cyclotron Range of Frequency (ICRF) heating conducted in 1999 in the 3rd experimental campaign on the Large Helical Device (LHD) with an emphasis on the optimization of the heating regime. Specifically, an exhaustive study of seven different heating regimes was carried out by changing the RF frequency relative to the magnetic field intensity, and the dependence of the heating efficiency on H-minority concentration was investigated. It was found in the experiment that both ion and electron heating are attainable with the same experimental setup by properly choosing the frequency relative to the magnetic field intensity. In the cases of both electron heating and ion heating, the power absorption efficiency depends on the minority ion concentration. An optimum minority concentration exists in the ion heating case while, in the electron heating case, the efficiency increases with concentration monotonically. A simple model calculation is introduced to provide a heuristic understanding of these experimental results. Among the heating regimes examined in this experiment, one of the ion heating regimes was finally chosen as the optimized heating regime and various high performance discharges were realized with it.
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