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Kobayashi, Takayuki; Sawahata, Masayuki; Terakado, Masayuki; Hiranai, Shinichi; Ikeda, Ryosuke; Oda, Yasuhisa; Wada, Kenji; Hinata, Jun; Yokokura, Kenji; Hoshino, Katsumichi; et al.
Proceedings of 40th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz 2015) (USB Flash Drive), 3 Pages, 2015/08
A gyrotron for electron cyclotron heating and current drive (ECH/CD) has been developed for JT-60SA (Super-Advanced). In high-power, long-pulse operations, oscillations of 1 MW/100 s have been demonstrated at both 110 GHz and 138 GHz, for the first time. These results fully satisfied the requirements for JT-60SA. Moreover, it was experimentally shown that the higher power operation at each frequency is expected to be acceptable for this gyrotron from the viewpoint of heat load at the cavity resonator, collector, and stray radiation absorbers. An oscillation at 82 GHz, which is an additional frequency, has been demonstrated up to 2 s at the output power of 0.4 MW, so far. High power experiments toward higher power of 1.5 MW (110/138 GHz) and 1 MW (82 GHz) are ongoing.
Sakamoto, Keishi; Takahashi, Koji; Kasugai, Atsushi; Minami, Ryutaro; Kobayashi, Noriyuki*; Nishio, Satoshi; Sato, Masayasu; Tobita, Kenji
Fusion Engineering and Design, 81(8-14), p.1263 - 1270, 2006/02
Times Cited Count：6 Percentile：36.38(Nuclear Science & Technology)no abstracts in English
Moriyama, Shinichi; Ikeda, Yoshitaka; Seki, Masami; Sakamoto, Keishi; Kasugai, Atsushi; Takahashi, Koji; Kajiwara, Ken*; Isayama, Akihiko; Suzuki, Takahiro; Fukuda, Takeshi*; et al.
Purazuma, Kaku Yugo Gakkai-Shi, 79(9), p.935 - 944, 2003/09
An optimization of current profile is a key issue for attaining higher plasma performance in Tokamak, such as stabilization of neo-classical tearing mode (NTM) and control of internal transport barrier (ITB). In JT-60U, a high power electron cyclotron heating (ECH) system at 110 GHz has been developed for local plasma heating and current drive. We have demonstrated the technical feasibility of the antenna which can scan EC beam in both toroidal and poloidal directions. The toroidal scan enabled co- and counter- current drive and also pure plasma heating. An automatic stabilization of the NTM was demonstrated by means of current drive at the location of magnetic island using a feedback control of poloidal beam angle. The total injected power has been extended to 2.8 MW for 3.6 sec and each gyrotron delivers ~ 1 MW for 5 sec. This world record of the injection energy was attained by an upgrade of the gyrotron using RF absorber in the beam tunnel to suppress the parasitic oscillation and improvement of the transmission efficiency of the waveguide system.
Kasugai, Atsushi; Sakamoto, Keishi; Hayashi, Kenichi*; Takahashi, Koji; Shoyama, Hiroaki*; Kajiwara, Ken*; Ikeda, Yoshitaka; Kariya, Tsuyoshi*; Mitsunaka, Yoshika*; Fujii, Tsuneyuki; et al.
JAERI-Research 2002-027, 57 Pages, 2002/11
JAERI-Research-2002-027.pdf:3.6MB
no abstracts in English
Takahashi, Koji; Komatsuzaki, Manabu*
JAERI-Research 2000-054, 23 Pages, 2001/03
JAERI-Research-2000-054.pdf:1.37MB
no abstracts in English
Takahashi, Koji; Sakamoto, Keishi; Kasugai, Atsushi; Imai, Tsuyoshi; Brandon, J. R.*; Sussmann, R. S.*
Review of Scientific Instruments, 71(11), p.4139 - 4143, 2000/11
Times Cited Count：14 Percentile：62.96(Instruments & Instrumentation)no abstracts in English
Takahashi, Koji; Imai, Tsuyoshi; Mori, Kensuke*; Mori, Seiji*; Nomoto, Yasunobu*
JAERI-Research 2000-036, 26 Pages, 2000/09
JAERI-Research-2000-036.pdf:1.24MB
no abstracts in English
Kobayashi, Takayuki; Hiranai, Shinichi; Sawahata, Masayuki; Terakado, Masayuki; Wada, Kenji; Hinata, Jun; Sato, Fumiaki; Yokokura, Kenji; Hoshino, Katsumichi; Takahashi, Koji; et al.
no journal, ,
A mechanical structure of the launcher for electron cyclotron heating and current drive in JT-60SA has been designed to realize wide range of poloidal and toroidal injection angles with high reliability. One of the key components is a bellows structure (vacuum boundary) enabling linear and rotation motions of the rigid shaft. A full scale mock-up of the bellows structure has been fabricated and tested. The linear motion was repeated 100,000 cycles and the rotation motion was repeated 10,000 cycles. In this test, no evidence of vacuum leakage was observed. Then, the mock-up has been extended up to the first mirror including full length of the steering shaft (~4 m) and bearings. The cyclic test of the full system of the driving structure will be carried out in 2015. A mock-up of M2, which is a large curved mirror including four cooling channels, has been designed and fabricated. It was experimentally confirmed that the flow rate of each cooling channels was consistent with the design.
