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Watanabe, Tomohiko*; Idomura, Yasuhiro; Todo, Yasushi*; Honda, Mitsuru*
Nihon Genshiryoku Gakkai-Shi ATOMO
, 64(3), p.152 - 156, 2022/03
Understanding of physical processes of particle, momentum, and thermal transports is essential for predicting the confinement performance of burning plasmas in ITER, which is targeting the scientific demonstration of magnetic confinement fusion. First principles based simulations on Fugaku disclosed physical mechanisms such as complex transport processes of multi-scale turbulence in deuterium-tritium plasmas and kinetic effects in energetic particle transport due to electromagnetic fluctuations. We promote further research and development of first principles based simulations towards the performance prediction of burning plasmas.
Idomura, Yasuhiro; Watanabe, Tomohiko*; Todo, Yasushi*
Shimyureshon, 38(2), p.79 - 86, 2019/06
We promote the research and development of exascale fusion plasma simulations on Post-K towards estimation and prediction of core plasma performance, and exploration of improved operation scenarios on the next generation fusion experimental reactor ITER. In this paper, we review developed exascale simulation technologies and outcomes from validation studies on existing experimental devices, and discuss perspectives on exascale fusion plasma simulations on Post-K.
Ishizawa, Akihiro*; Idomura, Yasuhiro; Imadera, Kenji*; Kasuya, Naohiro*; Kanno, Ryutaro*; Satake, Shinsuke*; Tatsuno, Tomoya*; Nakata, Motoki*; Nunami, Masanori*; Maeyama, Shinya*; et al.
Purazuma, Kaku Yugo Gakkai-Shi, 92(3), p.157 - 210, 2016/03
The high-performance computer system Helios which is located at The Computational Simulation Centre (CSC) in The International Fusion Energy Research Centre (IFERC) started its operation in January 2012 under the Broader Approach (BA) agreement between Japan and the EU. The Helios system has been used for magnetised fusion related simulation studies in the EU and Japan and has kept high average usage rate. As a result, the Helios system has contributed to many research products in a wide range of research areas from core plasma physics to reactor material and reactor engineering. This project review gives a short catalogue of domestic simulation research projects. First, we outline the IFERC-CSC project. After that, shown are objectives of the research projects, numerical schemes used in simulation codes, obtained results and necessary computations in future.
shear Alfv
n modes driven by energetic N-NB ions in JT-60UBierwage, A.; Todo, Yasushi*; Aiba, Nobuyuki; Shinohara, Koji
Nuclear Fusion, 54(10), p.104001_1 - 104001_14, 2014/10
Times Cited Count：19 Percentile：65.87(Physics, Fluids & Plasmas)n eigenmodes in a DIII-D experimentTodo, Yasushi*; Van Zeeland, M. A.*; Bierwage, A.; Heidbrink, W. W.*
Nuclear Fusion, 54(10), p.104012_1 - 104012_13, 2014/10
Times Cited Count：48 Percentile：89.56(Physics, Fluids & Plasmas)Bierwage, A.; Shinohara, Koji; Todo, Yasushi*; Yagi, Masatoshi
Proceedings of 25th IAEA Fusion Energy Conference (FEC 2014) (CD-ROM), 8 Pages, 2014/10
=1 energetic particle modes for N-NB ion dynamics in JT-60UBierwage, A.; Shinohara, Koji; Aiba, Nobuyuki; Todo, Yasushi*
Nuclear Fusion, 53(7), p.073007_1 - 073007_12, 2013/07
Times Cited Count：19 Percentile：62.58(Physics, Fluids & Plasmas)Bierwage, A.; Aiba, Nobuyuki; Shinohara, Koji; Todo, Yasushi*; Deng, W.*; Ishikawa, Masao; Matsunaga, Go; Yagi, Masatoshi
Proceedings of 24th IAEA Fusion Energy Conference (FEC 2012) (CD-ROM), 8 Pages, 2012/10
Bierwage, A.; Aiba, Nobuyuki; Todo, Yasushi*; Deng, W.*; Ishikawa, Masao; Matsunaga, Go; Shinohara, Koji; Yagi, Masatoshi
Plasma and Fusion Research (Internet), 7(Sp.1), p.2403081_1 - 2403081_4, 2012/07
Bierwage, A.; Todo, Yasushi*; Aiba, Nobuyuki; Shinohara, Koji; Ishikawa, Masao; Yagi, Masatoshi
Plasma and Fusion Research (Internet), 6, p.2403109_1 - 2403109_5, 2011/08
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
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
Fasoli, A.*; Gormezano, C.*; Berk, H. L.*; Breizman, B.*; Briguglio, S.*; Darrow, D. S.*; Gorelenkov, N.*; Heidbrink, W. W.*; Jaun, A.*; Konovalov, S. V.*; et al.
Nuclear Fusion, 47(6), p.S264 - S284, 2007/06
Times Cited Count：490 Percentile：84.21(Physics, Fluids & Plasmas)no abstracts in English
Ishikawa, Masao; Takechi, Manabu; Shinohara, Koji; Kusama, Yoshinori; Cheng, C. Z.*; Matsunaga, Go; Todo, Yasushi*; Gorelenkov, N. N.*; Kramer, G. J.*; Nazikian, R. M.*; et al.
Nuclear Fusion, 45(12), p.1474 - 1480, 2005/12
Times Cited Count：38 Percentile：74.20(Physics, Fluids & Plasmas)To investigate energetic ion transport induced by Alfven eigenmodes (AEs) the neutron emission profile measurement and the charge exchange (CX) neutral particle flux measurement by Natural Diamond Detector has been performed simultaneously in the JT-60U for the first time. The energetic ion profiles inferred from these measurements indicate that ALEs cause a radial redistribution of energetic ions of limited energy range from the core region to the outer region of the plasma in weak shear plasmas. This energy range is consistent with the resonance condition between the mode and the energetic ions. In reversed shear plasmas, reversed-shear-induced AEs (RSAEs) and their transition to TAEs as the minimum value of the safety factor decreases has been observed. Neutron measurements suggest energetic ion loss is large in the transition phase from RSAEs to TAEs.
n eigenmodes driven by negative-ion-based neutral beams in JT-60UShinohara, Koji; Ishikawa, Masao; Takechi, Manabu; Kusama, Yoshinori; Todo, Yasushi*; Gorelenkov, N. N.*; Cheng, C. Z.*; Fukuyama, Atsushi*; Kramer, G.*; Nazikian, R. M.*; et al.
Purazuma, Kaku Yugo Gakkai-Shi, 81(7), p.547 - 552, 2005/07
In the bursting instabilities in the frequency range of Alfven Eigenmode, we observed two types of modes phenomenologically. In one type, the time scale of the mode was 
1ms and the mode amplitude was so large that we were able to detect apparent enhanced transport of the energetic ions. The enhanced transport showed the clear energy dependence by using new diagnostics, natural diamond detector. In another type, the mode amplitude is not so large, compared with the first type. The frequency up-down chirping is clearly observed with the time-scale of a few ms. This frequency chirping was reproduced by the newly developed simulation code, MEGA To demonstrate this model of Reversed-Shear-induced Alfven Eigenmode, RSAE, we have performed experiments in the condition where we can have q profile with a good signal-to-noise ratio. We observed the slow up-frequency sweeping of RSAE due to the down evolution of qmin, We have analyzed this experiment by using NOVA-K code. We observed that the most unstable mode localized around qmin.
Todo, Yasushi*; Shinohara, Koji; Takechi, Manabu; Ishikawa, Masao
Physics of Plasmas, 12(1), p.012503_1 - 012503_7, 2005/01
Times Cited Count：56 Percentile：83.52(Physics, Fluids & Plasmas)Energetic-ion driven instability in a JT-60U plasma was investigated using a simulation code for magnetohydrodynamics and energetic particles. The spatial profile of the unstable mode peaks near the plasma center where the safety factor profile is flat and the spatial profile consists of a single primary harmonic m/n = 2/1. The real frequency of the unstable mode is close to the experimental starting frequency of the fast frequency sweeping mode. Simulation results demonstrate that energetic ion orbit width and energetic ion pressure significantly broaden radial profile of the unstable mode. For the smallest value among the investigated energetic ion orbit width, the unstable mode is localized within 20% of the minor radius. This gives an upper limit of the spatial profile width of the unstable mode which the magnetohydrodynamic effects alone can induce. For the experimental condition of the JT-60U plasma, energetic ions broaden the radial width of the unstable mode spatial profile by a factor of 3. The unstable mode is primarily induced by the energetic particles.
n eigenmodesTodo, Yasushi*; Nakajima, Noriyoshi*; Shinohara, Koji; Takechi, Manabu; Ishikawa, Masao; Yamamoto, Satoshi*
Proceedings of 20th IAEA Fusion Energy Conference (FEC 2004) (CD-ROM), 8 Pages, 2004/11
Linear properties and nonlinear evolutions of an energetic-ion driven instability in a JT-60U plasma were investigated using a simulation code for MHD and energetic particles. The spatial profile of the unstable mode peaks near the plasma center where the safety factor profile is flat. The real frequency of the mode is close to the experimental starting frequency of the fast frequency sweeping mode. The simulation results demonstrate that the energetic ion orbit width and the energetic ion pressure significantly broaden radial profile of the unstable mode. For the experimental condition of JT-60U, the energetic ions broaden the spatial profile of the unstable mode by a factor of 3. The unstable mode is primarily induced by the energetic particles. It is demonstrated that the frequency shifts both upward and downward in the nonlinear evolution at the rate close to that of the fast frequency sweeping mode. In addition to the energetic particle mode in JT-60U, an investigation of TAE in an LHD-like plasma using the simulation code for the helical coordinate system is reported.
Shinohara, Koji; Takechi, Manabu; Ishikawa, Masao; Kusama, Yoshinori; Tsuzuki, Kazuhiro; Urata, Kazuhiro*; Kawashima, Hisato; Tobita, Kenji; Fukuyama, Atsushi*; Cheng, C. Z.*; et al.
Plasma Physics and Controlled Fusion, 46(7), p.S31 - S45, 2004/07
Times Cited Count：43 Percentile：77.91(Physics, Fluids & Plasmas)Recent energetic particle physics research has been devoted to Alfven eigenmodes (AEs) in reversed-shear (RS) plasmas, energetic ion transport in the appearance of modes in the frequency range of TAE, energetic ion behavior in the plasma with a current hole, and ripple loss in the complex toroidal field ripple due to ferritic steel plates. We will report these recent progresses for energetic particle physics in JT-60U and JFT-2M.
Ide, Shunsuke; Okada, Hiroyuki*; Hirano, Yoichi*; Todo, Yasushi*; Norimatsu, Takayoshi*; Chikaraishi, Hirotaka*
Purazuma, Kaku Yugo Gakkai-Shi, 79(1), p.65 - 69, 2003/01
no abstracts in English
