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La Haye, R. J.*; Prater, R.*; Buttery, R. J.*; Hayashi, Nobuhiko; Isayama, Akihiko; Maraschek, M. E.*; Urso, L.*; Zohm, H.*
Nuclear Fusion, 46(4), p.451 - 461, 2006/04
Times Cited Count：151 Percentile：97.55(Physics, Fluids & Plasmas)no abstracts in English
Nagasaki, Kazunobu*; Isayama, Akihiko; Hayashi, Nobuhiko; Ozeki, Takahisa; Takechi, Manabu; Oyama, Naoyuki; Ide, Shunsuke; Yamamoto, Satoshi*; JT-60 Team
Proceedings of 20th IAEA Fusion Energy Conference (FEC 2004) (CD-ROM), 8 Pages, 2004/11
no abstracts in English
discharges and real-time control of current profile in JT-60USuzuki, Takahiro; Isayama, Akihiko; Sakamoto, Yoshiteru; Ide, Shunsuke; Fujita, Takaaki; Takenaga, Hidenobu; Luce, T. C.*; Wade, M. R.*; Oikawa, Toshihiro; Naito, Osamu; et al.
Proceedings of 20th IAEA Fusion Energy Conference (FEC 2004) (CD-ROM), 8 Pages, 2004/11
no abstracts in English
Suzuki, Takahiro; Oikawa, Toshihiro; Isayama, Akihiko; Fujita, Takaaki
Purazuma, Kaku Yugo Gakkai-Shi, 80(5), p.362 - 363, 2004/05
An analytical method to evaluate spatio-temporal change in current density profile directly from the motional Stark effect (MSE) diagnostic is applied to a discharge, where a neo-classical tearing mode (NTM) appeared and was stabilized by electron cyclotron current drive (ECCD). The analysis clearly shows spatially localized decrease in current density at the magnetic island location, implying decrease in bootstrap current due to flattening of pressure profile within the island. When the NTM is stabilized after the start of the ECCD application, increase in current density at the island location is observed.
Oikawa, Toshihiro
JAERI-Research 2003-028, 134 Pages, 2004/01
JAERI-Research-2003-028.pdf:7.73MB
The negative ion based neutral beam (N-NB) driven current density was determined over a wide range of electron temperatures. Theoretical prediction of the NB current drive increasing with beam energy and electron temperature was validated. A record value of NB current drive efficiency was achieved simultaneously with high confinement and high beta at a plasma current of 1.5 MA under a full current drive condition. The experimental validation of NB current drive theory gives greater confidence in predicting the NB current drive in future reactors. However, it was also found that MHD instabilities caused a degradation of NB current drive. A beam-driven instability expelled N-NB fast ions carrying non-inductive current from the central region. The lost N-NB driven current was estimated to be 7 % of the total N-NB driven current. For the neoclassical tearing mode (NTM), comparisons of the measurements with transport code calculations revealed that the loss of fast ions increases with the NTM activity and that fast ions at higher energies suffer larger transport than at lower energies.
ELMy H-mode discharges in JT-60UIsayama, Akihiko; Kamada, Yutaka; Hayashi, Nobuhiko; Suzuki, Takahiro; Oikawa, Toshihiro; Fujita, Takaaki; Fukuda, Takeshi; Ide, Shunsuke; Takenaga, Hidenobu; Ushigusa, Kenkichi; et al.
Nuclear Fusion, 43(10), p.1272 - 1278, 2003/10
Times Cited Count：130 Percentile：95.67(Physics, Fluids & Plasmas)no abstracts in English
Nagasaki, Kazunobu*; Isayama, Akihiko; Ide, Shunsuke; JT-60 Team
Nuclear Fusion, 43(10), p.L7 - L10, 2003/10
Times Cited Count：48 Percentile：79.65(Physics, Fluids & Plasmas)no abstracts in English
Kamada, Yutaka
Purazuma, Kaku Yugo Gakkai-Shi, 79(2), p.123 - 135, 2003/02
This paper reviews recent studies on tokamak MHD stability towards achievement of high beta steady-state, where profile control of current, pressure and rotation, and optimization of the plasma shape play fundamental roles. The key instabilities are the neoclassical tearing mode, the resistive wall mode, the edge localized modes etc. Towards demonstration of an economically attractive tokamak reactor, we need to increase the beta value with sufficiently high integrated plasma performance. Towards this goal, studies on stability control in the self-regulating plasma system are essential.
Isayama, Akihiko; Nagasaki, Kazunobu*; Ide, Shunsuke; Fukuda, Takeshi*; Suzuki, Takahiro; Seki, Masami; Moriyama, Shinichi; Ikeda, Yoshitaka; JT-60 Team
AIP Conference Proceedings 694, p.321 - 324, 2003/00
no abstracts in English
Iio, Shunji*; Ide, Shunsuke; Ozeki, Takahisa; Sugihara, Masayoshi; Takase, Yuichi*; Takeji, Satoru*; Tobita, Kenji; Fukuyama, Atsushi*; Miyamoto, Kenro*
Purazuma, Kaku Yugo Gakkai-Shi, 78(6), P. 601, 2002/06
no abstracts in English
Takei, Nahoko; Ozeki, Takahisa; Smolyakov, A. I.*; Isayama, Akihiko; Hayashi, Nobuhiko; Iio, Shunji*; Shimada, Ryuichi*
Journal of Plasma and Fusion Research SERIES, Vol.5, p.386 - 389, 2002/00
no abstracts in English
H-mode discharges in JT-60UIsayama, Akihiko; Kamada, Yutaka; Ozeki, Takahisa; Ide, Shunsuke; Fujita, Takaaki; Oikawa, Toshihiro; Suzuki, Takahiro; Neyatani, Yuzuru; Isei, Nobuaki; Hamamatsu, Kiyotaka; et al.
Nuclear Fusion, 41(6), p.761 - 768, 2001/06
Times Cited Count：50 Percentile：80.13(Physics, Fluids & Plasmas)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
H-mode discharges by the first harmonic electron cyclotron heating/current drive on JT-60UIsayama, Akihiko; Kamada, Yutaka; Ide, Shunsuke; Hamamatsu, Kiyotaka; Oikawa, Toshihiro; Suzuki, Takahiro; Neyatani, Yuzuru; Ozeki, Takahisa; Ikeda, Yoshitaka; Kajiwara, Ken; et al.
Plasma Physics and Controlled Fusion, 42(12), p.L37 - L45, 2000/12
Times Cited Count：152 Percentile：95.56(Physics, Fluids & Plasmas)no abstracts in English
H-mode discharges in JT-60UIsayama, Akihiko; Kamada, Yutaka; Ozeki, Takahisa; Ide, Shunsuke; Fujita, Takaaki; Oikawa, Toshihiro; Suzuki, Takahiro; Neyatani, Yuzuru; Isei, Nobuaki; Hamamatsu, Kiyotaka; et al.
IAEA-CN-77/EXP3/03 (CD-ROM), 5 Pages, 2000/00
no abstracts in English
Idei, Hiroshi*; Moriyama, Shinichi; Kobayashi, Takayuki; Isayama, Akihiko; Sakaguchi, Masatsugu*; Kasparek, W.*
no journal, ,
A FAst DIrectional Switch (FADIS) performance based on steep slope in a diplexer function has been considered for dual-frequency (dual-f) applications to switch the transmission line with small frequency control. A diplexer of a FADIS using a Square Corrugated Waveguide (SCW) splitter was designed as one of most attractive candidates for the dual-f operation on the JT-60SA system. The splitter performance was a key issue for the dual-f operation, and extended operation regions in splitter operations have been considered using mode contents analyses based on matching coefficient evaluation. Some operational branches with high matching coefficients (
0.9) were found, and new operation parameters were proposed for the dual-f application. Radiation pattern distributions from the SCW splitter were defined very well with no serious side lobes. Double loop resonant ring system has been proposed with the SCW splitter for the dual-f operation.
