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Oct 13 – 18, 2014
Hotel Park Inn Pribaltiyskaya
Europe/Moscow timezone

Development of Over 1 MW and Multi-Frequency Gyrotrons for Fusion

Oct 16, 2014, 8:30 AM
Green 8-9 (Hotel Park Inn Pribaltiyskaya)

Green 8-9

Hotel Park Inn Pribaltiyskaya

Saint Petersburg, Russian Federation
Poster Poster 5


Prof. Tsuyoshi IMAI (University of Tsukuba)


EC (Electron Cyclotron) scheme is quite promising tool for heating and current drive (H&CD) and plasma control for present and future devices up to Demo and Commercial reactors. Development of gyrotron is a key to open this promising door. Multi-MW and multi-frequency technologies are major issues to challenge for robust and cost effective reactor heating system. In University of Tsukuba, gyrotrons of wide range of frequencies from 14 GHz to 300 GHz have been developed for this purpose in collaboration with JAEA, NIFS and TETD. Over-1 MW dual frequency gyrotron of new frequency range (14 – 35 GHz), where the reduction of diffraction loss and cathode optimization are quite important, has been developed for EC/EBW H&CD for GAMMA 10/PDX, QUEST, Heliotron J and NSTX-U. Output power of 1.25 MW at 28 GHz and estimated oscillation power of 1.2 MW at 35.45 GHz from the same tube have been achieved with the cathode angle improvement. This is the first demonstration of the over 1 MW dual-frequency operations in lower frequency, which contributes to the technology of wide band multi-frequency/multi-MW tube for Demo EC/EBW H&CD. The output power of 600 kW for 2 s at 28 GHz is also demonstrated. It is applied to the QUEST and has resulted higher EC-driven current than ever. Further, in the joint program of NIFS and Tsukuba for LHD ECH gyrotrons, a new frequency of 154 GHz has been successfully developed with a TE_28,8 cavity, which delivered 1.16 MW for 1 s, 0.3 MW in CW (30 minutes), and the total power of 4.4 MW to LHD plasma with other three 77 GHz tubes, which extended the LHD plasma to high T_e region. All these gyrotron performances are new records in each frequency range.
Paper Number FIP/2-2Rc
Country or International Organisation Japan

Primary author

Prof. Tsuyoshi IMAI (University of Tsukuba)


Prof. Fumimichi SANO (Kyoto University) Prof. Hideki ZUSHI (Kyushu University) Dr Hiroe IGAMI (National Institute for Fusion Science) Dr Hiromi TAKAHASHI (National Institute for Fusion Science) Prof. Hiroshi IDEI (Kyushu University) Prof. Kazunobu NAGASAKI (Kyoto University) Prof. Keishi SAKAMOTO (Japan Atomic Energy Agency) Prof. Makoto ICHIMURA (University of Tsukuba) Prof. Masayuki ONO (Princeton University Plasma Physics Laboratory) Dr Ryutarou MINAMI (University of Tsukuba) Mr Satoshi ITO (National Institute for Fusion Science) Prof. Shin KUBO (National Institute for Fusion Science) Mr Takaki KATO (University of Tsukuba) Prof. Takashi MUTOH (National Institute for Fusion Science) Prof. Takashi SHIMOZUMA (National Institute for Fusion Science) Mr Taku EGUCHI (University of Tsukuba) Dr Tomoharu NUMAKURA (University of Tsukuba) Prof. Tsuyoshi KARIYA (University of Tsukuba) Prof. Yasuo YOSHIMURA (National Institute for Fusion Science) Mr Yoichi ENDO (University of Tsukuba) Dr Yoshika MITSUNAKA (Toshiba Electron Tubes and Devices Co., Ltd)

Presentation materials