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Hada, Kazuyoshi*; Nagasaki, Kazunobu*; Masuda, Kai*; Kobayashi, Shinji*; Ide, Shunsuke; Isayama, Akihiko; Kajiwara, Ken
Fusion Science and Technology, 67(4), p.693 - 704, 2015/05
Times Cited Count：10 Percentile：64.00(Nuclear Science & Technology)no abstracts in English
Suzuki, Takahiro; Nagasaki, Kazunobu*
Purazuma, Kaku Yugo Gakkai-Shi, 88(11), p.657 - 659, 2012/11
no abstracts in English
Hada, Kazuyoshi*; Nagasaki, Kazunobu*; Masuda, Kai*; Kinjo, Ryota*; Ide, Shunsuke; Isayama, Akihiko
Plasma and Fusion Research (Internet), 7(Sp.1), p.2403104_1 - 2403104_5, 2012/07
no abstracts in English
Maekawa, Takashi*; Ide, Shunsuke; Kajiwara, Ken; Nagasaki, Kazunobu*; Isayama, Akihiko; Hada, Kazuyoshi*
Purazuma, Kaku Yugo Gakkai-Shi, 87(10), p.671 - 681, 2011/10
no abstracts in English
Isayama, Akihiko; Sakakibara, Satoru*; Furukawa, Masaru*; Matsunaga, Go; Yamazaki, Kozo*; Watanabe, Kiyomasa*; Idomura, Yasuhiro; Sakamoto, Yoshiteru; Tanaka, Kenji*; Tamura, Naoki*; et al.
Purazuma, Kaku Yugo Gakkai-Shi, 86(6), p.374 - 377, 2010/06
no abstracts in English
Osakabe, Masaki*; Shinohara, Koji; Toi, Kazuo*; Todo, Yasushi*; Hamamatsu, Kiyotaka; Murakami, Sadayoshi*; Yamamoto, Satoshi*; Idomura, Yasuhiro; Sakamoto, Yoshiteru; Tanaka, Kenji*; et al.
Purazuma, Kaku Yugo Gakkai-Shi, 85(12), p.839 - 842, 2009/12
no abstracts in English
Isayama, Akihiko; Matsunaga, Go; Kobayashi, Takayuki; Moriyama, Shinichi; Oyama, Naoyuki; Sakamoto, Yoshiteru; Suzuki, Takahiro; Urano, Hajime; Hayashi, Nobuhiko; Kamada, Yutaka; et al.
Nuclear Fusion, 49(5), p.055006_1 - 055006_9, 2009/05
Times Cited Count：63 Percentile：89.91(Physics, Fluids & Plasmas)no abstracts in English
Idomura, Yasuhiro; Yoshida, Maiko; Yagi, Masatoshi*; Tanaka, Kenji*; Hayashi, Nobuhiko; Sakamoto, Yoshiteru; Tamura, Naoki*; Oyama, Naoyuki; Urano, Hajime; Aiba, Nobuyuki; et al.
Purazuma, Kaku Yugo Gakkai-Shi, 84(12), p.952 - 955, 2008/12
no abstracts in English
Isayama, Akihiko; Suzuki, Takahiro; Hayashi, Nobuhiko; Ide, Shunsuke; Hamamatsu, Kiyotaka; Fujita, Takaaki; Hosoyama, Hiroki; Kamada, Yutaka; Nagasaki, Kazunobu*; Oyama, Naoyuki; et al.
AIP Conference Proceedings 933, p.229 - 236, 2007/10
no abstracts in English
Motojima, Osamu*; Yamada, Hiroshi*; Komori, Akio*; Oyabu, Nobuyoshi*; Muto, Takashi*; Kaneko, Osamu*; Kawahata, Kazuo*; Mito, Toshiyuki*; Ida, Katsumi*; Imagawa, Shinsaku*; et al.
Nuclear Fusion, 47(10), p.S668 - S676, 2007/10
Times Cited Count：34 Percentile：73.51(Physics, Fluids & Plasmas)The performance of net-current free heliotron plasmas has been developed by findings of innovative operational scenarios in conjunction with an upgrade of the heating power and the pumping/fuelling capability in the Large Helical Device (LHD). Consequently, the operational regime has been extended, in particular, with regard to high density, long pulse length and high beta. Diversified studies in LHD have elucidated the advantages of net-current free heliotron plasmas. In particular, an internal diffusion barrier (IDB) by a combination of efficient pumping of the local island divertor function and core fuelling by pellet injection has realized a super dense core as high as 5
10
m
, which stimulates an attractive super dense core reactor. Achievements of a volume averaged beta of 4.5% and a discharge duration of 54 min with a total input energy of 1.6 GJ (490 kW on average) are also highlighted. The progress of LHD experiments in these two years is overviewed by highlighting IDB, high-beta and long pulse.
Isayama, Akihiko; Oyama, Naoyuki; Urano, Hajime; Suzuki, Takahiro; Takechi, Manabu; Hayashi, Nobuhiko; Nagasaki, Kazunobu*; Kamada, Yutaka; Ide, Shunsuke; Ozeki, Takahisa
Nuclear Fusion, 47(8), p.773 - 782, 2007/08
Times Cited Count：29 Percentile：68.87(Physics, Fluids & Plasmas)Results from active control of neoclassical tearing modes (NTMs) by electron cyclotron current drive (ECCD) in 
are described. Evolution of an NTM with the poloidal mode number 
and the toroidal mode number 
has been suppressed by ECCD inside the sawtooth inversion radius in the co-direction, showing the possibility of the coexistence of sawtooth oscillations and a small-amplitude 
NTM without large confinement degradation. Stabilization of an 
NTM by ECCD at the mode rational surface has been demonstrated with a small value of the ratio of the current density driven by electron cyclotron (EC) wave to the local bootstrap current density (
). Also, dependence of the stabilization effect on ECCD location has been investigated in detail, and it has been clarified that an NTM can be completely stabilized with the misalignment of the ECCD location less than about half of the island width, and that the NTM is destabilized with the misalignment comparable to the island width. Time-dependent, self-consistent simulation of magnetic island evolution using the TOPICS code has shown that the above stabilization and destabilization of an NTM are well reproduced with the same set of coefficients of the modified Rutherford equation. The TOPICS simulation has also clarified that EC wave power required for complete stabilization can be significantly reduced by narrowing the ECCD width.
Prater, R.*; La Haye, R. J.*; Luce, T. C.*; Petty, C. C.*; Strait, E. J.*; Ferron, J. R.*; Humphreys, D. A.*; Isayama, Akihiko; Lohr, J.*; Nagasaki, Kazunobu*; et al.
Nuclear Fusion, 47(5), p.371 - 377, 2007/05
Times Cited Count：59 Percentile：87.25(Physics, Fluids & Plasmas)The 
/
neoclassical tearing mode (NTM) has been observed to strongly degrade confinement and frequently lead to a disruption in high 
discharges in DIII-D if allowed to grow to large size. Stabilization of grown NTMs by application of highly localized electron cyclotron current drive (ECCD) at the island location has led to operation at increased plasma pressure, up to the no-wall kink limit. After the NTM is stabilized by the ECCD, the correct location for the current drive is maintained using information from real-time equilibrium reconstructions which include measurements from the motional Stark effect diagnostic. This same process is used alternatively to prevent the mode from ever growing, leading to performance at the pressure limit in high performance hybrid discharges with above 4%. Modeling using the modified Rutherford equation shows that the required power is in close agreement with the experimental threshold for prevention of the 2/1 NTM.
Motojima, Osamu*; Yamada, Hiroshi*; Komori, Akio*; Oyabu, Nobuyoshi*; Kaneko, Osamu*; Kawahata, Kazuo*; Mito, Toshiyuki*; Muto, Takashi*; Ida, Katsumi*; Imagawa, Shinsaku*; et al.
Proceedings of 21st IAEA Fusion Energy Conference (FEC 2006) (CD-ROM), 12 Pages, 2007/03
The performance of net-current free Heliotron plasmas has been developed by findings of innovative operational scenarios in conjunction with an upgrade of the heating power and the pumping/fueling capability in the Large Helical Device (LHD). Consequently, the operational regime has been extended, in particular, with regard to high density, long pulse length and high beta. Diversified studies in LHD have elucidated the advantages of net-current free heliotron plasmas. In particular, an Internal Diffusion Barrier (IDB) by combination of efficient pumping of the local island divertor function and core fueling by pellet injection has realized a super dense core as high as 510m, which stimulates an attractive super dense core reactor. Achievements of a volume averaged beta of 4.5 % and a discharge duration of 54-min. with a total input energy of 1.6 GJ (490 kW in average) are also highlighted. The progress of LHD experiments in these two years is overviewed with highlighting IDB, high and long pulse.
Prater, R.*; La Haye, R. J.*; Luce, T. C.*; Petty, C. C.*; Strait, E. J.*; Ferron, J. R.*; Humphreys, D. A.*; Isayama, Akihiko; Lohr, J.*; Nagasaki, Kazunobu*; et al.
Proceedings of 21st IAEA Fusion Energy Conference (FEC 2006) (CD-ROM), 8 Pages, 2007/03
Onset of the m/n=2/1 neoclassical tearing mode (NTM) has been prevented in high-performance DIII-D discharges using localized electron cyclotron current drive (ECCD). Active tracking of the 
=2 surface location, using real-time equilibrium reconstructions with motional Stark effect data, allows the current drive to be maintained at the rational surface even in the absence of a detectable mode. With the application of this technique in DIII-D hybrid discharges, the 2/1 mode is avoided and good energy confinement is maintained for more than 1 second with at the estimated n=1 no-wall stability limit for ideal kink modes (
approximately equals 3.9 % and normalized beta 
approximately equals 3.2). The results can be understood through modeling using the modified Rutherford equation.
Isayama, Akihiko; Oyama, Naoyuki; Urano, Hajime; Suzuki, Takahiro; Takechi, Manabu; Hayashi, Nobuhiko; Nagasaki, Kazunobu*; Kamada, Yutaka; Ide, Shunsuke; Ozeki, Takahisa; et al.
Proceedings of 21st IAEA Fusion Energy Conference (FEC 2006) (CD-ROM), 8 Pages, 2007/03
no abstracts in English
Kimura, Haruyuki; Inutake, Masaaki*; Kikuchi, Mitsuru; Ogawa, Yuichi*; Kamada, Yutaka; Ozeki, Takahisa; Naito, Osamu; Takase, Yuichi*; Ide, Shunsuke; Nagasaki, Kazunobu*; et al.
Purazuma, Kaku Yugo Gakkai-Shi, 83(1), p.81 - 93, 2007/01
no abstracts in English
Isayama, Akihiko; Oyama, Naoyuki; Urano, Hajime; Suzuki, Takahiro; Takechi, Manabu; Ide, Shunsuke; Kamada, Yutaka; Ozeki, Takahisa; Nagasaki, Kazunobu*; JT-60 Team
Plasma and Fusion Research (Internet), 1(6), p.030_1 - 030_3, 2006/06
no abstracts in English
Nagasaki, Kazunobu*; Isayama, Akihiko; Hayashi, Nobuhiko; Ozeki, Takahisa; Takechi, Manabu; Oyama, Naoyuki; Ide, Shunsuke; Yamamoto, Satoshi*; JT-60 Team
Nuclear Fusion, 45(12), p.1608 - 1617, 2005/12
Times Cited Count：32 Percentile：69.23(Physics, Fluids & Plasmas)no abstracts in English
Yoshikawa, Kiyoshi*; Takiyama, Ken*; Onishi, Masami*; Yamamoto, Yasushi*; Nagasaki, Kazunobu*; Masuda, Kai*; Toku, Hisayuki*; Horiike, Hiroshi*
JAERI-Tech 2005-006, 116 Pages, 2005/03
JAERI-Tech-2005-006.pdf:24.79MB
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
