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Kikuchi, Mitsuru; Azumi, Masafumi*
Frontiers in Fusion Research, 2; Introduction to Modern Tokamak Physics, 402 Pages, 2015/09
This book is a textbook on modern tokamak plasma physics for graduate students and researchers based on our Reviews of Modern Physics (2012).
Kikuchi, Mitsuru; Azumi, Masafumi*
Reviews of Modern Physics, 84(4), p.1807 - 1854, 2012/12
Times Cited Count：54 Percentile：87.77(Physics, Multidisciplinary)Tokamak uses transformer action for plasma confinement. So, it is proposed to use non-inductive current drive including bootstrap current to achieve steady state operation. This paper reviews the progress of steady state tokamak research focused on theoretical aspect for 20 years since my proposal in 1990.
Honda, Mitsuru; Kikuchi, Mitsuru; Azumi, Masafumi*
Nuclear Fusion, 52(2), p.023021_1 - 023021_12, 2012/02
Times Cited Count：23 Percentile：69.37(Physics, Fluids & Plasmas)Tani, Keiji; Azumi, Masafumi*
Nuclear Fusion, 48(8), p.085001_1 - 085001_9, 2008/08
Times Cited Count：15 Percentile：51.25(Physics, Fluids & Plasmas)Simulation studies are made for alpha-driven currents in tokamak reactors by using an orbit-following Monte-Carlo code. The finite banana width of alpha particles causes an asymmetry particle trapping and consequently an alpha current is driven by the imbalance of transit particles. The current driven by alpha transit particles (simply referred to as transit current) is greatly enhanced by a collaborative effect of the finite banana-width trajectories and a non-uniformity of alpha particle source. The pitch-angle scattering is also very important for the transit current. Fusion produced alpha particles can drive substantial current to assist the bulk bootstrap current in steady state tokamak reactors.
Ishii, Yasutomo; Azumi, Masafumi; Smolyakov, A. I.*
Nuclear Fusion, 47(8), p.1024 - 1032, 2007/08
Times Cited Count：9 Percentile：32.07(Physics, Fluids & Plasmas)no abstracts in English
Ishii, Yasutomo; Azumi, Masafumi; Smolyakov, A. I.*
Proceedings of 21st IAEA Fusion Energy Conference (FEC 2006) (CD-ROM), 8 Pages, 2007/03
no abstracts in English
Ishii, Yasutomo; Azumi, Masafumi*; Smolyakov, A. I.*
Journal of Plasma Physics, 72(6), p.1243 - 1248, 2006/12
Times Cited Count：1 Percentile：3.54(Physics, Fluids & Plasmas)no abstracts in English
Muraoka, Katsunori*; Azumi, Masafumi; Suzuki, Keizo*; Yamagata, Yukihiko*; Yagi, Masatoshi*
Journal of Physics D; Applied Physics, 39(10), p.2135 - 2139, 2006/05
Times Cited Count：6 Percentile：24.6(Physics, Applied)A model is presented to explain the mechanism of striation formation in ac plasma display panel discharges. A simple Monte Carlo simulation code follows the electron motions in such discharges and features of striations obtained by the simulation are consistent with experimental results. The model suggests the indirect measurement of electric field in a micro-discharges from the space pich of striations.
analyses with ferromagnetic and plasma rotation effects and wall geometry for a high steady state tokamakKurita, Genichi; Bialek, J.*; Tsuda, Takashi; Azumi, Masafumi*; Ishida, Shinichi; Navratil, G. A.*; Sakurai, Shinji; Tamai, Hiroshi; Matsukawa, Makoto; Ozeki, Takahisa; et al.
Nuclear Fusion, 46(2), p.383 - 390, 2006/02
Times Cited Count：9 Percentile：31.21(Physics, Fluids & Plasmas)It is shown that critical beta is decreased by ferromagnetic effect by about 8% for 
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2, and denoting the permeability of ferromagnetic wall and vacuum, respectively, for tokamak of aspect ratio 3. The existence of the stability window for resistive wall mode opened by both effects of the toroidal plasma rotation and the plasma dissipation, which was not observed for high aspect ratio tokamak, is found for tokamak of aspect ratio 3. The effect of ferromagnetism on them is also investigated. The critical beta analyses of NCT (National Centralized Tokamak) plasma using VALEN code are started with stabilizing plate and vacuum vessel geometry with finite resistivity, and the results for passive effect of stabilizing plate are obtained. The calculations including stabilizing effect of the vacuum-vessel and also active feedback control are also performed for present design of NCT plasma.
analyses with ferromagnetic and plasma rotation effects and wall geometry for a high steady state tokamakKurita, Genichi; Bialek, J.*; Tsuda, Takashi; Azumi, Masafumi; Ishida, Shinichi; Navratil, G. A.*; Sakurai, Shinji; Tamai, Hiroshi; Matsukawa, Makoto; Ozeki, Takahisa; et al.
IAEA-CN-116/FT/P7-7 (CD-ROM), 8 Pages, 2004/11
The critical beta is shown to be decreased by ferromagnetic effect by about 8 % for m/m02, m and m0 denote the permeability of ferromagnetic wall and vacuum, respectively, for tokamak of aspect ratio 3. The existence of the stability window opened by both effects of the toroidal plasma rotation and the plasma dissipation, which was not observed for high aspect ratio tokamak, is found for tokamak of aspect ratio 3. The effect of ferromagnetism on them is also investigated. The critical beta analyses of NCT (National Centralized Tokamak) plasma using VALEN code are started with stabilizing plate and vacuum vessel geometry with finite resistivity, and the results for passive effect of stabilizing plate are obtained. The calculations including stabilizing effect of the vacuum-vessel and also active feedback control are also performed for present design of NCT plasma.
Azumi, Masafumi
Purazuma, Kaku Yugo Gakkai-Shi, 80(5), p.378 - 381, 2004/05
Progress of large scale scientific simulation environment in JAERI is briefly described. The expansion of fusion simulation science have been played a key role in the increasing performances of super computers and computer network system in JAERI. Both scalar parallel and vector parallel computer systems are now working in Naka and Tokai sites respectively and, particle and fluid simulation codes developed under the fusion simulation project, NEXT, are running on each system. The storage grid system has been also successfully developed for the effective visualization analysis by remote users. Fusion research is going to enter the new phase of ITER, and the need for the super computer system with higher performance are increasing more than as ever along with the development of reliable simulation models.
Ishii, Yasutomo; Azumi, Masafumi; Kishimoto, Yasuaki
Theory of Fusion Plasmas, ISPP21, p.213 - 226, 2004/00
no abstracts in English
Kurita, Genichi; Tsuda, Takashi; Azumi, Masafumi; Ishida, Shinichi; Takeji, Satoru*; Sakasai, Akira; Matsukawa, Makoto; Ozeki, Takahisa; Kikuchi, Mitsuru
Nuclear Fusion, 43(9), p.949 - 954, 2003/09
Times Cited Count：31 Percentile：67.25(Physics, Fluids & Plasmas)In order to improve economic and environmental suitability of tokamak fusion reactors, both the accomplishment of high beta plasmas and the practical use of low activation materials to reduce the amount of radioactive waste are crucially important. Low radio-activation ferritic steel is considered as a most promising candidate for structural material in DEMO reactors, and there is the possibility of reduction of critical beta value by the deterioration of MHD stability due to ferromagnetism of ferritic steel. This paper investigates the effect of ferromagnetism with plasma flow on the beta limit of tokamak plasma by carrying out MHD stability analyses including ferromagnetic and plasma flow effects.
Ishii, Yasutomo; Azumi, Masafumi; Kishimoto, Yasuaki
Physics of Plasmas, 10(9), p.3512 - 3520, 2003/09
Times Cited Count：12 Percentile：37.11(Physics, Fluids & Plasmas)no abstracts in English
tearing modes in the Japan atomic research institute fusion Torus-2 modifiedBakhtiari, M.; Azumi, Masafumi; Tsuzuki, Kazuhiro; Kamiya, Kensaku; Kawashima, Hisato; Kusama, Yoshinori; Sato, Masayasu; Hoshino, Katsumichi; JFT-2M Group
Physics of Plasmas, 10(8), p.3212 - 3216, 2003/08
Times Cited Count：15 Percentile：44.16(Physics, Fluids & Plasmas)The Tearing mode equation is solved in presence of a ferromagnetic resistive wall to study the effect of the ferromagnetism on the Tearing mode stability. It is shown that a ferromagnetic wall has a weak effect on the surface Tearing modes depending on the curent profile.
Ishii, Yasutomo; Azumi, Masafumi; Kishimoto, Yasuaki; Leboeuf, J. N.*
Nuclear Fusion, 43(7), p.539 - 546, 2003/07
no abstracts in English
Ishii, Yasutomo; Azumi, Masafumi; Kishimoto, Yasuaki; Leboeuf, J. N.*
Nuclear Fusion, 43(7), p.539 - 546, 2003/07
Times Cited Count：26 Percentile：61.38(Physics, Fluids & Plasmas)no abstracts in English
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
Azumi, Masafumi
Purazuma, Kaku Yugo Gakkai-Shi, 77(5), p.457 - 463, 2001/05
no abstracts in English
Ishii, Yasutomo; Azumi, Masafumi; Kishimoto, Yasuaki
Journal of Plasma and Fusion Research SERIES, Vol.4, p.271 - 275, 2001/00
no abstracts in English
