Refine your search:     
Report No.
 - 
Search Results: Records 1-20 displayed on this page of 25

Presentation/Publication Type

Initialising ...

Refine

Journal/Book Title

Initialising ...

Meeting title

Initialising ...

First Author

Initialising ...

Keyword

Initialising ...

Language

Initialising ...

Publication Year

Initialising ...

Held year of conference

Initialising ...

Save select records

Journal Articles

Exascale simulations of fusion 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.

Journal Articles

Progress report of Japanese simulation research projects using the high-performance computer system Helios in the International Fusion Energy Research Centre

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.

Journal Articles

Dynamics of low-$$n$$ shear Alfv$'e$n modes driven by energetic N-NB ions in JT-60U

Bierwage, A.; Todo, Yasushi*; Aiba, Nobuyuki; Shinohara, Koji

Nuclear Fusion, 54(10), p.104001_1 - 104001_14, 2014/10

 Times Cited Count:14 Percentile:64.41(Physics, Fluids & Plasmas)

Journal Articles

Multi-phase simulation of fast ion profile flattening due to Alfv$'e$n eigenmodes in a DIII-D experiment

Todo, Yasushi*; Van Zeeland, M. A.*; Bierwage, A.; Heidbrink, W. W.*

Nuclear Fusion, 54(10), p.104012_1 - 104012_13, 2014/10

 Times Cited Count:37 Percentile:90.55(Physics, Fluids & Plasmas)

Journal Articles

Multi-time-scale energetic particle dynamics in JT-60U simulated with MHD activity, sources and collisions

Bierwage, A.; Shinohara, Koji; Todo, Yasushi*; Yagi, Masatoshi

Proceedings of 25th IAEA Fusion Energy Conference (FEC 2014) (CD-ROM), 8 Pages, 2014/10

Journal Articles

Role of convective amplification of $$n$$=1 energetic particle modes for N-NB ion dynamics in JT-60U

Bierwage, A.; Shinohara, Koji; Aiba, Nobuyuki; Todo, Yasushi*

Nuclear Fusion, 53(7), p.073007_1 - 073007_12, 2013/07

 Times Cited Count:14 Percentile:59.76(Physics, Fluids & Plasmas)

Journal Articles

Nonlinear simulation of energetic particle modes in JT-60U

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

Journal Articles

Nonlinear simulation of energetic particle modes in high-beta tokamak plasma

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

Journal Articles

Nonlinear hybrid simulations of energetic particle modes in realistic tokamak flux surface geometry

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

Journal Articles

29th report of ITPA topical group meeting

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

Journal Articles

27th report of ITPA topical group meeting

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

Journal Articles

Report on ITPA meetings, 24

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

Journal Articles

Progress in the ITER physics basis, 5; Physics of energetic ions

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:370 Percentile:85.96(Physics, Fluids & Plasmas)

no abstracts in English

Journal Articles

Energetic ion transport by abrupt large-amplitude event induced by negative-ion-based neutral beam injection in the JT-60U

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:37 Percentile:76.55(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.

Journal Articles

Instability in the frequency range of Alfv$'e$n eigenmodes driven by negative-ion-based neutral beams in JT-60U

Shinohara, 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.

Journal Articles

Nonlocal energetic particle mode in a JT-60U plasma

Todo, Yasushi*; Shinohara, Koji; Takechi, Manabu; Ishikawa, Masao

Physics of Plasmas, 12(1), p.012503_1 - 012503_7, 2005/01

 Times Cited Count:46 Percentile:81.78(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.

Journal Articles

Nonperturbative effects of energetic ions on Alfv$'e$n eigenmodes

Todo, 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.

Journal Articles

Energetic particle physics in JT-60U and JFT-2M

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:40 Percentile:79.05(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.

Journal Articles

19th IAEA Fusion Energy Conference Report

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

Oral presentation

Instability in the frequency range of Alfv$'e$n eigenmode driven by Negative-ion-based Neutral Beam in JT-60U

Shinohara, Koji; Ishikawa, Masao; Takechi, Manabu; Kusama, Yoshinori; Todo, Yasushi*; Fukuyama, Atsushi*; Matsunaga, Go; Ozeki, Takahisa

no journal, , 

no abstracts in English

25 (Records 1-20 displayed on this page)