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Fujita, Takaaki; Suzuki, Takahiro; Oikawa, Toshihiro; Isayama, Akihiko; Hatae, Takaki; Naito, Osamu; Sakamoto, Yoshiteru; Hayashi, Nobuhiko; Hamamatsu, Kiyotaka; Ide, Shunsuke; et al.
Physical Review Letters, 95(7), p.075001_1 - 075001_4, 2005/08
Times Cited Count：14 Percentile：60.90(Physics, Multidisciplinary)We found that no current can be driven in a central region of high-temperature, magnetically-confined, axi-symmetric torus plasma once the central current density becomes nearly zero ("current hole"), in spite of high electric conductivity. The current clamp was observed against current drive by a toroidal electric field and a radio-frequency wave in experiments on the JT-60U tokamak. This is a new, stiff, self-organized structure of magnetic field in an axi-symmetric torus plasma.
Tobita, Kenji; Ozeki, Takahisa; Nakamura, Yukiharu
Plasma Physics and Controlled Fusion, 46(7), p.S95 - S105, 2004/07
Times Cited Count：10 Percentile：31.94(Physics, Fluids & Plasmas)no abstracts in English
Shiraiwa, Shunichi*; Ide, Shunsuke; Ito, Satoshi*; Mitarai, Osamu*; Naito, Osamu; Ozeki, Takahisa; Sakamoto, Yoshiteru; Suzuki, Takahiro; Takase, Yuichi*; Tanaka, Shigetoshi*; et al.
Physical Review Letters, 92(3), p.035001_1 - 035001_4, 2004/01
Times Cited Count：48 Percentile：83.56(Physics, Multidisciplinary)no abstracts in English
Sengoku, Seio
Denki Gakkai Purazuma Kenkyukai Shiryo (PST-03-41), p.23 - 26, 2003/09
no abstracts in English
Takase, Yuichi*; JT-60 Team
AIP Conference Proceedings 694, p.235 - 242, 2003/05
A central electron temperature of 23 keV was obtained by EC wave injection. A highly localized current density profile was obtained by central ECCD, indicating an upper limit on the diffusion coefficient for resonant electrons of 
. The experimentally obtained current drive figure of merit was lower than theoretical prediction, possibly because of the negative loop voltage induced by overdrive. A comparison of HFS and LFS off-axis ECCD confirmed the theoretically expected trapped particle effect on the current drive efficiency. Offaxis LHCD was used to broaden the qmin radius and the ITB foot radius. N-NBCD was used to shrink the current hole radius. An integrated scenario consisting of (1) a novel plasma start-up method using RF plasma production and induction by vertical field and shaping coils, (2) a noninductive ramp-up stage, and (3) a transition to a high-density, bootstrap-dominated, highconfinement plasma, without the use of the OH solenoid, has been demonstrated. The plasma created by this technique had both internal and edge transport barriers, with 
(
), 
, 
and 
at 
MA and 
.
Ninomiya, Hiromasa
Nihon Genshiryoku Gakkai-Shi, 45(4), p.243 - 248, 2003/04
no abstracts in English
Nakamura, Yukiharu; Tsutsui, Hiroaki*; Takei, Nahoko*; Sakamoto, Yoshiteru; Fujita, Takaaki; Sugihara, Masayoshi; Ozeki, Takahisa; Tobita, Kenji; Konishi, Satoshi; Iio, Shunji*; et al.
Europhysics Conference Abstracts, 27A, 4 Pages, 2003/00
no abstracts in English
Fujita, Takaaki
Nihon Butsuri Gakkai-Shi, 57(8), p.559 - 567, 2002/08
In a tokamak, one of toroidal shaped magnetic confinement systems, a large toroidal current induced in a high temperature plasma produces helical magnetic fields to confine the plasma itself. Therefore, the spatial structure of confining magnetic fields can be determined by measuring the profile of the plasma current. This can lead to the understanding of the transport and stability properties of the plasma. In this review, a novel technique using the motional Stark effect to measure the current profile in the JT-60 tokamak is shown. With the aid of this technique, a new operational mode of a tokamak, with which the plasma confinement can be substantially improved, has been discovered. Recent experimental results of confinement improvement with the current profile control are presented.
Chankin, A. V.; Mukhovatov, V. S.*; Fujita, Takaaki; Miura, Yukitoshi
Europhysics Conference Abstracts (CD-ROM), 26B, 4 Pages, 2002/00
no abstracts in English
Miura, Yukitoshi; Fujita, Takaaki; Oikawa, Toshihiro; Suzuki, Takahiro; Ide, Shunsuke; Sakamoto, Yoshiteru; Koide, Yoshihiko; Hatae, Takaki; Naito, Osamu; Isayama, Akihiko; et al.
IAEA-CN-94/EX/C3-1Ra (CD-ROM), 5 Pages, 2002/00
no abstracts in English
Fujita, Takaaki; Miura, Yukitoshi; Suzuki, Takahiro; Ide, Shunsuke; Takenaga, Hidenobu; Oikawa, Toshihiro; Chankin, A. V.; Sakamoto, Yoshiteru; Koide, Yoshihiko; Hatae, Takaki; et al.
Proceedings of 29th European Physical Society Conference on Plasma Physics and Controlled Fusion, 9 Pages, 2002/00
no abstracts in English
Fujita, Takaaki; Oikawa, Toshihiro; Suzuki, Takahiro; Ide, Shunsuke; Sakamoto, Yoshiteru; Koide, Yoshihiko; Hatae, Takaki; Naito, Osamu; Isayama, Akihiko; Hayashi, Nobuhiko; et al.
Physical Review Letters, 87(24), p.245001_1 - 245001_4, 2001/12
Times Cited Count：183 Percentile：96.08(Physics, Multidisciplinary)no abstracts in English
