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Oda, Yasuhisa*; Komurasaki, Kimiya*; Takahashi, Koji; Kasugai, Atsushi; Imai, Tsuyoshi*; Sakamoto, Keishi
Denki Gakkai Rombunshi, A, 126(8), p.807 - 812, 2006/08
Experiments on microwave plasma generation and its application to microwave beamed energy propulsion were conducted using a 1MW-class, 170GHz gyrotron. The microwave beam was focused using a parabola reflector and plasma was initiated near the focal point in the ambient air. Plasma propagated upstream in the microwave beam channel while absorbing microwave. Its propagation velocity was supersonic when the microwave power density was larger than 75kW/cm
. The propulsive impulse was measured using a cone-cylinder shaped thruster model. As a result, maximum momentum coupling coefficient was obtained at a certain plasma propagation distance. In addition, large momentum coupling coefficient was obtained when plasma was propagated at a supersonic velocity. It would be because supersonic plasma propagation forms a strong shock wave, resulting in an efficient pressure increase.
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
Oda, Yasuhisa*; Ushio, Masato*; Komurasaki, Kimiya*; Takahashi, Koji; Kasugai, Atsushi; Sakamoto, Keishi
AIP Conference Proceedings 766, p.297 - 302, 2005/04
no abstracts in English
Sakamoto, Keishi; Kasugai, Atsushi; Minami, Ryutaro; Takahashi, Koji; Kobayashi, Noriyuki*
Journal of Physics; Conference Series, 25, p.8 - 12, 2005/00
The present status of ITER gyrotron development of JAERI is reported. Up to now, we demonstrated 100 sec operation at 0.5 MW level power output. On the other hand, some issues were recognized for CW operation, i.e., the beam current decreased as pulse duration expanded. And the large amount of stray RF of 170 GHz exists in the gyrotron. Former, pre-programming control of the heater power of electron gun was introduced to keep the beam current constant. Latter, the inner surface of the radiator was optimized to minimize the diffraction, and loss was reduced by 1/5. Prior to the RF pulse extension, we tried an electron beam test without RF oscillation. As a result, the constant beam current was demonstrated up to 1000 sec.
Kasugai, Atsushi; Minami, Ryutaro; Takahashi, Koji; Kobayashi, Noriyuki*; Kariya, Tsuyoshi*; Mitsunaka, Yoshika*; Hayashi, Kenichi*; Sakamoto, Keishi
Shingaku Giho, 104(520), p.37 - 42, 2004/12
no abstracts in English
Oda, Yasuhisa*; Komurasaki, Kimiya*; Takahashi, Koji; Kasugai, Atsushi; Sakamoto, Keishi
Denki Gakkai Kenkyukai Shiryo, Genshiryoku Kenkyukai (NE-04-11
15), p.19 - 22, 2004/09
no abstracts in English
Minami, Ryutaro; Kobayashi, Noriyuki*; Sakamoto, Keishi; Kasugai, Atsushi; Takahashi, Koji; Imai, Tsuyoshi
JAERI-Research 2004-006, 17 Pages, 2004/03
JAERI-Research-2004-006.pdf:1.37MB
no abstracts in English
Kajiwara, Ken; Ikeda, Yoshitaka; Sakamoto, Keishi; Kasugai, Atsushi; Seki, Masami; Moriyama, Shinichi; Takahashi, Koji; Imai, Tsuyoshi; Mitsunaka, Yoshika*; Fujii, Tsuneyuki
Fusion Engineering and Design, 65(4), p.493 - 499, 2003/07
Times Cited Count：11 Percentile：33.33(Nuclear Science & Technology)no abstracts in English
Terakado, Masayuki; Shimono, Mitsugu; Igarashi, Koichi*; Takahashi, Masami*; Ishii, Kazuhiro*; Seki, Masami
Heisei-14-Nendo Tokyo Daigaku Sogo Gijutsu Kenkyukai Gijutsu Hokokushu, 3 Pages, 2003/03
no abstracts in English
Hirata, Yosuke*; Mitsunaka, Yoshika*; Hayashi, Kenichi*; Ito, Yasuyuki*; Sakamoto, Keishi; Imai, Tsuyoshi
IEEE Transactions on Plasma Science, 31(1), p.142 - 145, 2003/02
Times Cited Count：11 Percentile：34.28(Physics, Fluids & Plasmas)no abstracts in English
Oda, Yasuhisa*; Nakagawa, Tatsuo*; Matsui, Makoto*; Komurasaki, Kimiya*; Takahashi, Koji; Sakamoto, Keishi; Imai, Tsuyoshi
Dai-47-Kai Uchu Kagaku Gijutsu Rengo Koenkai Koenshu (CD-ROM), p.1067 - 1069, 2003/00
no abstracts in English
Matsui, Makoto*; Mihara, Yorichika*; Nakagawa, Tatsuo*; Mori, Koichi*; Komurasaki, Kimiya*; Takahashi, Koji; Sakamoto, Keishi; Imai, Tsuyoshi
Uchu Yuso Shimpojiumu (Heisei-14-Nendo) Koenshu, p.300 - 303, 2003/00
no abstracts in English
Sakamoto, Keishi; Kasugai, Atsushi; Ikeda, Yoshitaka; Hayashi, Kenichi*; Takahashi, Koji; Kajiwara, Ken; Moriyama, Shinichi; Seki, Masami; Kariya, Tsuyoshi*; Mitsunaka, Yoshika*; et al.
Proceedings of 19th IAEA Fusion Energy Conference (FEC 2002) (CD-ROM), 5 Pages, 2002/10
The development of a key EC component, 1 MW gyrotron, and integration of the EC technologies on JT-60U EC system have been carried out. In the development of 1 MW gyrotron, the output of 1.3 MW was achieved. In pulse extension experiment, the outputs of 0.9 MW for 9.2 second and 0.5 MW for 30 sec. at 170 GHz, and 1.2 MW for 4.1 sec. at 110 GHz. In the JT-60U EC system, the maximum injection performances were 3 MW for 2sec, and contributed to produce high electron temperature plasma of 26 keV.
Ikeda, Yoshitaka; Kasugai, Atsushi; Moriyama, Shinichi; Kajiwara, Ken*; Seki, Masami; Tsuneoka, Masaki*; Takahashi, Koji; Anno, Katsuto; Hamamatsu, Kiyotaka; Hiranai, Shinichi; et al.
Fusion Science and Technology (JT-60 Special Issue), 42(2-3), p.435 - 451, 2002/09
Times Cited Count：26 Percentile：82.31(Nuclear Science & Technology)no abstracts in English
Shimono, Mitsugu; Seki, Masami; Terakado, Masayuki; Igarashi, Koichi*; Ishii, Kazuhiro*; Kajiwara, Ken; Anno, Katsuto
NIFS-MEMO-36, p.382 - 385, 2002/06
no abstracts in English
Seki, Masami; Moriyama, Shinichi; Kajiwara, Ken; Ikeda, Yoshitaka; Sakamoto, Keishi; Imai, Tsuyoshi; Fujii, Tsuneyuki
Journal of Plasma and Fusion Research SERIES, Vol.5, p.337 - 341, 2002/00
no abstracts in English
mode with depressed collectorShoyama, Hiroaki; Sakamoto, Keishi; Hayashi, Kenichi*; Kasugai, Atsushi; Tsuneoka, Masaki; Takahashi, Koji; Ikeda, Yukiharu; Kariya, Tsuyoshi*; Mitsunaka, Yoshika*; Imai, Tsuyoshi
Japanese Journal of Applied Physics, Part 2, 40(8B), p.L906 - L908, 2001/08
Times Cited Count：28 Percentile：71.93(Physics, Applied)no abstracts in English
Imai, Tsuyoshi; Kobayashi, Noriyuki*; Temkin, R.*; Thumm, M.*; Tran, M. Q.*; Alikaev, V.*
Fusion Engineering and Design, 55(2-3), p.281 - 289, 2001/07
Times Cited Count：52 Percentile：94.92(Nuclear Science & Technology)no abstracts in English
Kasugai, Atsushi; Sakamoto, Keishi; Takahashi, Koji; Kajiwara, Ken; Shoyama, Hiroaki; Ikeda, Yukiharu; Tsuneoka, Masaki; Ikeda, Yoshitaka; Fujii, Tsuneyuki; Kariya, Tsuyoshi*; et al.
Fusion Engineering and Design, 53(1-4), p.399 - 406, 2001/01
Times Cited Count：17 Percentile：74.85(Nuclear Science & Technology)no abstracts in English
Isayama, Akihiko; Ikeda, Yoshitaka; Ide, Toshiyuki; Suzuki, Takahiro; Moriyama, Shinichi; Takahashi, Koji; Kajiwara, Ken; Oikawa, Toshihiro; Hamamatsu, Kiyotaka; Kamada, Yutaka; et al.
AIP Conference Proceedings 595, p.267 - 274, 2001/00
no abstracts in English
