Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Nuga, Hideo; Matsuyama, Akinobu; Yagi, Masatoshi; Fukuyama, Atsushi*
Plasma and Fusion Research (Internet), 10, p.1203006_1 - 1203006_2, 2015/01
Takechi, Manabu; Fujita, Takaaki; Ishii, Yasutomo; Ozeki, Takahisa; Suzuki, Takahiro; Isayama, Akihiko; JT-60 Team
Nuclear Fusion, 45(12), p.1694 - 1699, 2005/12
Times Cited Count：7 Percentile：24.62(Physics, Fluids & Plasmas)High performance reversed shear discharges with strong internal transport barrier (ITB) and flat pressure profile in the plasma core region disrupt frequently even with low beta. We analyzed MHD instabilities leading to low beta disruption with measuring fluctuations and current profile with MSE measurement. We mainly observed two type of disruptions. One is the disruption without precursor at 
. The other is the disruption with n=1 precursor of 
100 ms. To explain these characteristics of disruption, we introduce the simple model such as, disruption occurs when the both MHD instabilities at plasma surface and at safety factor being equal to surface mode are unstable. This simple model can explain almost all observed disruption by two process. One is the surface mode triggered disruption, which occurs when qeff change, corresponding q surface at ITB layer changes discretely. The other is the internal mode triggered disruption, which occurs when corresponding q surface become unstable gradually.
Kawano, Yasunori
Denki Gakkai Gijutsu Hokoku, Dai-1018-Go, p.25 - 29, 2005/05
Aims of "The Investigation Committee on Pulsed Power Generation and Application" are to investigate recent developments on generation and control of pulsed power, to clarify the technological issues, and to provide the future prospects of such research area. This paper is written as the "section 3.3 Optical Diagnostics" in the technical report of the committee. Here, "diagnostics of relativistic electron beam in a torus plasma by laser inverse Compton scattering" is reported. This method has been newly proposed by JAERI for active measurement of the energy distribution of runaway electrons in a tokamak plasma. The paper presents the basic properties of scattered photons estimated in the case of runaway electron beam observed in JT-60U (number of beam electrons=2e17 electrons, beam electron energy = 30 MeV). For instance, when we use the fundamental YAG laser with the energy of 10 J/pulse and pulse widths of 1 ns, maximum energy of scattered photons would be in the X-ray region, and the signal to noise ratio can be estimated as 
3. It is also mentioned that the development of the pulse X-ray imaging spectroscopy is required for this diagnostics method.
Kawano, Yasunori; Kawahata, Kazuo*; Kusama, Yoshinori; Sasao, Mamiko*; Sugie, Tatsuo; Mase, Atsushi*; Asakura, Nobuyuki; Kato, Takako*; Takamura, Shuichi*; Tanabe, Tetsuo*; et al.
Purazuma, Kaku Yugo Gakkai-Shi, 81(2), p.128 - 130, 2005/02
no abstracts in English
Kawano, Yasunori; Nakano, Tomohide; Isayama, Akihiko; Hatae, Takaki; Konoshima, Shigeru; Oyama, Naoyuki; Kondoh, Takashi; Tamai, Hiroshi; Kubo, Hirotaka; Asakura, Nobuyuki; et al.
Europhysics Conference Abstracts (CD-ROM), 29C, 4 Pages, 2005/00
In order to mitigate the post-disruption runaway electrons, experiments has been carried out with impurity pellet injection. As a result, we have observed the prompt exhaust of the runaway electrons and the reduction of runaway plasma. We have presented one possible explanation for basic behavior of the runaway plasma current that it follows the balance of the avalanche generation of runaway electrons and their slowing down predicted by the model, including effects by synchrotron radiation. On the other hand, standing on the fact that the current quench time is extended by runaway electrons, the experiment for avoiding the current quench by runaway electrons has been carried out. The runaway electrons reinforced the discharge to survive against the low Te of less than several tens eV and an additional impurity pellet injection, and thus the plasma current was maintained and terminated as programmed. To study the dynamics of runaway electrons precisely, a new active and direct diagnostic concept using the laser inverse Compton scattering has been proposed.
Takei, Nahoko; Nakamura, Yukiharu; Tsutsui, Hiroaki*; Yoshino, Ryuji; Kawano, Yasunori; Ozeki, Takahisa; Tobita, Kenji; Iio, Shunji*; Shimada, Ryuichi*; Jardin, S. C.*
Plasma Physics and Controlled Fusion, 46(12), p.1815 - 1830, 2004/12
Times Cited Count：3 Percentile：9.99(Physics, Fluids & Plasmas)no abstracts in English
Asakura, Nobuyuki; Iio, Shunji*; Ozeki, Takahisa; Ono, Yasushi*; Kato, Takako*; Kawano, Yasunori; Sugihara, Masayoshi; Takamura, Shuichi*; Tanabe, Tetsuo*; Nakajima, Noriyoshi*; et al.
Purazuma, Kaku Yugo Gakkai-Shi, 80(7), P. 642, 2004/07
no abstracts in English
Sakakibara, Satoru*; Kurihara, Kenichi
Purazuma, Kaku Yugo Gakkai-Shi, 80(5), p.364 - 371, 2004/05
This article presents recent progress in magnetic measurements at magnetic confinement systems. The drift-problem of the integrator used in magnetic measurements is one of the major problems for plasma control and estimation of equilibrium parameters in long-pulse operation. In addition, the durability of the sensors such as a magnetic probe, a flux loop, etc., under fusion neutron irradiation environments is also important. The present status of the developments of a long-pulse integrator and a magnetic sensor are reported.
reversed shear plasmasTakei, Nahoko; Nakamura, Yukiharu; Kawano, Yasunori; Tsutsui, Hiroaki*; Ozeki, Takahisa; Tobita, Kenji; Sugihara, Masayoshi; Iio, Shunji*; Shimada, Ryuichi*; Jardin, S. C.*
Europhysics Conference Abstracts, 28G, 4 Pages, 2004/00
no abstracts in English
Takei, Nahoko; Nakamura, Yukiharu; Kawano, Yasunori; Tsutsui, Hiroaki*; Ozeki, Takahisa; Tobita, Kenji; Sugihara, Masayoshi; Iio, Shunji*; Shimada, Ryuichi*; Jardin, S. C.*
Journal of Plasma and Fusion Research SERIES, Vol.6, p.554 - 557, 2004/00
no abstracts in English
Ishii, Yasutomo; Azumi, Masafumi; Kishimoto, Yasuaki
Theory of Fusion Plasmas, ISPP21, p.213 - 226, 2004/00
no abstracts in English
Asakura, Nobuyuki; Kato, Takako*; Takamura, Shuichi*; Tanabe, Tetsuo*; Higashijima, Satoru; Iio, Shunji*; Ozeki, Takahisa; Ono, Yasushi*; Kawano, Yasunori; Nakajima, Noriyoshi*; et al.
Purazuma, Kaku Yugo Gakkai-Shi, 79(11), p.1194 - 1196, 2003/11
The ITPA (International Tokamak Physics Activity) meeting was held at Scientific Educational Center of Ioffe Institute (St. Petersburg) in Russia. In the meeting, topical physics group meetings of "Scrape-off-layer and Divertor Physics", "MHD, Disruptions and Control", "Energetic Particles, Heating and Steady State Operation", and "Diagnostics" were carried out. The joint meeting for plasma control was also held. In getting many participants from Japan, Europe, Russia, ITER international team, U.S.A. and China (observer), the active discussions were carried out. The outline of discussions in each topical group and in the plasma control joint meeting is reported here.
Ishii, Yasutomo; Azumi, Masafumi; Kishimoto, Yasuaki; Leboeuf, J. N.*
Nuclear Fusion, 43(7), p.539 - 546, 2003/07
no abstracts in English
Takamura, Shuichi*; Wakatani, Masahiro*; Ninomiya, Hiromasa; Kamada, Yutaka; Yatsu, Kiyoshi*; Hatae, Takaki; Sugihara, Masayoshi; Iio, Shunji*; Ozeki, Takahisa; Kawano, Yasunori
Purazuma, Kaku Yugo Gakkai-Shi, 79(1), P. 70, 2003/01
no abstracts in English
Kawano, Yasunori; Sugihara, Masayoshi; Ozeki, Takahisa; Shimada, Michiya
Proceedings of 30th EPS Conference on Controlled Fusion and Plasma Physics (CD-ROM), 4 Pages, 2003/00
Since the major disruption determines key designing conditions of a vacuum vessel and plasma facing components of the tokamak fusion reactor, it is essential to understand the characteristics of major disruption. For this purpose, a disruption database has been constructed covering most of high performance discharges in JT-60U. By database analysis, for disruptions during the reverse shear discharges, we have found that fast current quench tends to occur at the regime of surface safety factor of just around 4 and internal inductance of around 0.5. This knowledge will provide basis to investigate the physics of current quench in the reverse shear discharges.
Ishii, Yasutomo; Azumi, Masafumi; Kishimoto, Yasuaki
Physical Review Letters, 89(20), p.205002_1 - 205002_4, 2002/11
Times Cited Count：104 Percentile：92.6(Physics, Multidisciplinary)no abstracts in English
Bakhtiari, M.; Kawano, Yasunori; Tamai, Hiroshi; Miura, Yushi; Yoshino, Ryuji; Nishida, Yasushi*
Nuclear Fusion, 42(10), p.1197 - 1204, 2002/10
Times Cited Count：49 Percentile：80.12(Physics, Fluids & Plasmas)no abstracts in English
Kawano, Yasunori; Yoshino, Ryuji; Neyatani, Yuzuru; Nakamura, Yukiharu; Tokuda, Shinji; Tamai, Hiroshi
Fusion Science and Technology (JT-60 Special Issue), 42(2-3), p.298 - 314, 2002/09
Times Cited Count：13 Percentile：63.36(Nuclear Science & Technology)no abstracts in English
Tamai, Hiroshi; Yoshino, Ryuji; Tokuda, Shinji; Kurita, Genichi; Neyatani, Yuzuru; Bakhtiari, M.; Khayratdinov, R. R.*; Lukash, V.*; Rosenbluth, M. N.*; JT-60 Team
Nuclear Fusion, 42(3), p.290 - 294, 2002/03
Times Cited Count：34 Percentile：70.69(Physics, Fluids & Plasmas)no abstracts in English
Urata, Kazuhiro*; Suzuki, Yutaka*; Kudo, F.*; Kimura, Haruyuki; Miura, Yukitoshi; Yamamoto, Masahiro
Fusion Engineering and Design, 56-57, p.849 - 853, 2001/10
Times Cited Count：4 Percentile：33.39(Nuclear Science & Technology)no abstracts in English
