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Author(s):
T. Imai , T. Kariya , R. Minami , H. Shidara , K. Sakamoto, S. Kubo, T. Shimozuma, T. Mutoh, H. Takahashi, Y. Mitsunaka, Y. Endo , M. Harigae , M. Nakamura , Y. Sakagoshi , N. Murofushi , M. Ichimura , Y. Nakashima , M. Yoshikawa , Y. Yamaguchi and GAMMA 10 group
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Title:
Development of 1MW Gyrotron and Progress of ECH System for the GAMMA 10 Tandem Mirror in Tsukuba
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Date of publication:
Oct. 2008
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Key words:
21 IAEA Fusion Energy Conference, FT/P2-25
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Abstract:
High power gyrotrons with TE4,2 cavity at 28 GHz and with TE18,6 cavity and a diamond window at 77 GHz have been developed for GAMMA 10 and LHD in the joint program of NIFS and University of Tsukuba. The maximum outputs of 570 kW at 28 GHz and 1.1 MW at 77 GHz were obtained corresponding to each design. The operations of more than 750 kW for 5 sec. and 810 kW for 3.5 sec. were achieved in the developing tubes at 77 GHz, which is the first high power-long pulse result of the 77 GHz tube. The experimental simulation of the effect of the stray RF in the 28 GHz tube indicates the stray RF is the one of the major causes limiting gyrotron performance. The output of more than 1 MW with 40% oscillation efficiency is expected from the design of the next 28GHz gyrotron for GAMMA 10. Installation of the polarizer in the transmission line enhanced the performance of the ECH system in GAMMA 10, that is the first result which clearly showed ~100% X mode excitation is a key to design the efficient fundamental ECH system of strong field side injection in mirror devices.
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