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Maeyama, Shinya*; Watanabe, Tomohiko*; Nakata, Motoki*; Nunami, Masanori*; Asahi, Yuichi; Ishizawa, Akihiro*
Nature Communications (Internet), 13, p.3166_1 - 3166_8, 2022/06
Times Cited Count：14 Percentile：93.39(Multidisciplinary Sciences)Turbulent transport is a key physics process for confining magnetic fusion plasma. Recent theoretical and experimental studies of existing fusion experimental devices revealed the existence of cross-scale interactions between small (electron)-scale and large (ion)-scale turbulence. Since conventional turbulent transport modelling lacks cross-scale interactions, it should be clarified whether cross-scale interactions are needed to be considered in future experiments on burning plasma, whose high electron temperature is sustained with fusion-born alpha particle heating. Here, we present supercomputer simulations showing that electron scale turbulence in high electron temperature plasma can affect the turbulent transport of not only electrons but also fuels and ash. Electron-scale turbulence disturbs the trajectories of resonant electrons responsible for ion-scale micro-instability and suppresses large-scale turbulent fluctuations. Simultaneously, ion-scale turbulent eddies also suppress electron-scale turbulence. These results indicate a mutually exclusive nature of turbulence with disparate scales. We demonstrate the possibility of reduced heat flux via cross-scale interactions.
Miura, Yukitoshi
RIST News, (61), p.1 - 2, 2016/07
no abstracts in English
Takase, Kazuyuki; Ose, Yasuo*; Yoshida, Hiroyuki; Akimoto, Hajime; Satake, Shinichi*
Proceedings of International Conference on Jets, Wakes and Separated Flows (ICJWSF 2005), p.137 - 144, 2005/11
no abstracts in English
Maesako, Hiroshi*; Suzuki, Yoshio; Aoyagi, Tetsuo; Nakajima, Norihiro
Fujitsu, 55(2), p.109 - 115, 2004/03
ITBL (Information Technology Based Laboratory) project is promoted under the "e-Japan national priority program" by six research institutions. The project aims to construct a virtual laboratory which aid collaborative studies amongst researchers by allowing for sharing of intellectual properties and resources such as supercomputer hardware, software, data, etc. In order to realize this virtual laboratory environment, the Japan Atomic Energy Research Institute is developing an ITBL system infrastructure software system. Some of the highlighted functions offered by the ITBL infrastructure are: authentication for connecting to the supercomputers, parallel and distributed communication, job execution on the connected supercomputers, and formation of communities for aiding communication amongst researchers. In this passage, besides the introduction of the ITBL infrastructure, a brief introduction of the Quantum Bioinformatics and the Numerical Environmental Systems will be given as examples of the applications developed on the ITBL infrastructure.
Tani, Keiji
Dai-49-Kai Riron Oyo Rikigaku Koenkai Koen Rombunshu, p.313 - 316, 2001/00
no abstracts in English
Yokokawa, Mitsuo; Tani, Keiji
Joho Shori, 41(4), p.369 - 374, 2000/04
no abstracts in English
Tani, Keiji; Yokokawa, Mitsuo
Joho Shori, 41(3), p.249 - 254, 2000/03
no abstracts in English
Nakakawa, Masayuki;
Joho Shori, 36(2), p.137 - 142, 1995/02
no abstracts in English
AIP Conference Proceedings 248; Computer-aided Statistical Physics, p.136 - 142, 1992/00
no abstracts in English
; *
Proc. of the Int. Symp. on Supercomputing, p.253 - 257, 1991/00
no abstracts in English
Nakakawa, Masayuki; Mori, Takamasa; *
Prog. Nucl. Energy, 24, p.183 - 193, 1991/00
Times Cited Count：8 Percentile：64.43(Nuclear Science & Technology)no abstracts in English
Onodera, Naoyuki; Hasegawa, Yuta; Idomura, Yasuhiro; Asahi, Yuichi; Kawamura, Takuma; Ina, Takuya; Shimomura, Kazuya; Inagaki, Atsushi*; Suzuki, Shinichi*; Hirano, Kohin*; et al.
no journal, ,
Wind prediction based on digital twin is a promising technology that can contribute to the construction of new social infrastructures, including applications to smart city design and operation. In this poster presentation, we will introduce wind simulations based on data assimilation with observations and mesoscale meteorological data for the realization of a digital twin of wind conditions in urban areas.
Idomura, Yasuhiro
no journal, ,
The Gyrokinetic Toroidal 5D full-f Eulerian code GT5D was ported on Fugaku and Summit, which are state-of-the-art exascale supercomputers based on many core CPUs and GPUs. GT5D is based on a semi-implicit finite difference scheme, in which a stiff linear 4D convection operator is subject to implicit time integration, and the implicit finite difference solver for fast kinetic electrons occupies more than 80% of the total computing cost. The implicit solver was originally developed using a Krylov subspace method (GCR), in which global collective communication and halo data communication were bottlenecks on exascale supercomputers. This issue was resolved by a communication-avoiding Krylov subspace method (CA-GMRES), which reduces the number of global collective communication, and a FP16 preconditioner, which reduces the number of iterations and thus halo data communication. On Fugaku and Summit, the new CA-GMRES solver respectively achieved 
and 
speedups from the conventional GCR solver, and excellent strong scaling was obtained up to 5,760 CPUs/GPUs.
