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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

High-accuracy numerical integration of charged particle motion - with application to ponderomotive force

Furukawa, Masaru*; Matsuyama, Akinobu; Okawa, Yushiro*

Plasma and Fusion Research (Internet), 11, p.1303003_1 - 1303003_4, 2016/02

Journal Articles

Integrated modelling of toroidal rotation with the 3D non-local drift-kinetic code and boundary models for JT-60U analyses and predictive simulations

Honda, Mitsuru; Satake, Shinsuke*; Suzuki, Yasuhiro*; Yoshida, Maiko; Hayashi, Nobuhiko; Kamiya, Kensaku; Matsuyama, Akinobu; Shinohara, Koji; Matsunaga, Go; Nakata, Motoki; et al.

Nuclear Fusion, 55(7), p.073033_1 - 073033_11, 2015/07

 Times Cited Count:5 Percentile:29.96(Physics, Fluids & Plasmas)

Journal Articles

Chaos in runaway electron motion

Matsuyama, Akinobu

Purazuma, Kaku Yugo Gakkai-Shi, 91(3), p.204 - 208, 2015/03

no abstracts in English

Journal Articles

Fokker-Planck simulation of runaway electron generation in tokamak disruptions

Nuga, Hideo; Matsuyama, Akinobu; Yagi, Masatoshi; Fukuyama, Atsushi*

Plasma and Fusion Research (Internet), 10, p.1203006_1 - 1203006_2, 2015/01

Journal Articles

Drift resonance effect on stochastic runaway electron orbit in the presence of low-order magnetic perturbations

Matsuyama, Akinobu; Yagi, Masatoshi; Kagei, Yasuhiro; Nakajima, Noriyoshi*

Nuclear Fusion, 54(12), p.123007_1 - 123007_14, 2014/12

 Times Cited Count:10 Percentile:52.66(Physics, Fluids & Plasmas)

Journal Articles

Experimental analyses and predictive simulations of toroidal rotation driven by the neoclassical toroidal viscosity in rippled tokamaks

Honda, Mitsuru; Satake, Shinsuke*; Suzuki, Yasuhiro*; Matsunaga, Go; Shinohara, Koji; Yoshida, Maiko; Matsuyama, Akinobu; Ide, Shunsuke; Urano, Hajime

Nuclear Fusion, 54(11), p.114005_1 - 114005_14, 2014/11

 Times Cited Count:10 Percentile:52.66(Physics, Fluids & Plasmas)

Journal Articles

Integrated modeling of toroidal rotation with the 3D non-local drift-kinetic code and boundary models for JT-60U analyses and predictive simulations

Honda, Mitsuru; Satake, Shinsuke*; Suzuki, Yasuhiro*; Yoshida, Maiko; Hayashi, Nobuhiko; Kamiya, Kensaku; Matsuyama, Akinobu; Shinohara, Koji; Matsunaga, Go; Nakata, Motoki; et al.

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

Journal Articles

MHD instability excited by interplay between resistive wall mode and stable MHD modes in rotating tokamak plasmas

Aiba, Nobuyuki; Hirota, Makoto*; Matsuyama, Akinobu; Shiraishi, Junya; Bierwage, A.

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

A mechanism exciting magnetohydrodynamic (MHD) instabilities in rotating tokamak plasmas is found numerically for the first time. This mechanism is the interplay between a resistive wall mode (RWM) and a stable MHD mode. When the plasma has a stable discrete eigenmode, a reversed shear Alfv$'e$n eigenmode (RSAE) for example, a MHD mode is destabilized when plasma equilibrium rotation frequency is similar to the frequency of this stable eigenmode in a static equilibrium. This destabilization is also observed even when the eigenmode couples with Alfv$'e$n continua. This result suggests that for steady state high beta tokamaks, like DEMO, it is necessary to shape the safety factor profile in such a way that no stable eigenmode exists in the band of rotation frequency.

Journal Articles

Simulation study of nonlocal transport from edge to core in tokamak plasmas

Yagi, Masatoshi; Matsuyama, Akinobu; Miyato, Naoaki; Takizuka, Tomonori*

Contributions to Plasma Physics, 54(4-6), p.363 - 367, 2014/06

 Times Cited Count:0 Percentile:0.01(Physics, Fluids & Plasmas)

Journal Articles

Simulation study on nonlocal transport for peripheral density source

Yagi, Masatoshi; Miyato, Naoaki; Matsuyama, Akinobu; Takizuka, Tomonori*

Plasma and Fusion Research (Internet), 9, p.3403030_1 - 3403030_4, 2014/04

Journal Articles

Local gyrokinetic Vlasov simulations with realistic tokamak MHD equilibria

Nakata, Motoki; Matsuyama, Akinobu; Aiba, Nobuyuki; Maeyama, Shinya; Nunami, Masanori*; Watanabe, Tomohiko*

Plasma and Fusion Research (Internet), 9, p.1403029_1 - 1403029_12, 2014/04

A local gyrokinetic Vlasov simulation code GKV is extended to incorporate realistic tokamak equilibria including up-down asymmetry, which are produced by a free-boundary 2D Grad-Shafranov equation solver MEUDAS. The developed codes have been verified by a cross-code benchmark test using Cyclone-base-case like MHD equilibrium, where good agreement in the dispersion relation of ion temperature gradient (ITG) driven mode has been confirmed. The extended GKV is applied to two types of shaped plasmas expected in JT-60SA tokamak devices, i.e., ITER-like and highly-shaped plasmas, and ITG-mode stability and residual zonal-flow level are investigated. Through the detailed comparisons, more favorable stability properties against the ITG mode are revealed for the highly-shaped case, where the lower ITG-mode growth rate and higher residual zonal-flow levels compared to the ITER-like case are identified.

Journal Articles

Stochastic transport of runaway electrons due to low-order perturbations in tokamak disruption

Matsuyama, Akinobu; Yagi, Masatoshi; Kagei, Yasuhiro*

JPS Conference Proceedings (Internet), 1, p.015037_1 - 015037_4, 2014/03

no abstracts in English

Journal Articles

Relativistic guiding-center equations including slow equilibrium changes in magnetic coordinates

Matsuyama, Akinobu; Yagi, Masatoshi

Plasma and Fusion Research (Internet), 8, p.1403170_1 - 1403170_6, 2013/12

Oral presentation

Numerical simulation study on the orbit loss of runaway electron in ITER plasmas

Yagi, Masatoshi; Kagei, Yasuhiro*; Matsuyama, Akinobu

no journal, , 

In this presentation, the simulation results on the loss rate for runaway electrons in ITER plasmas will be reported. For this purpose, runaway electron orbit following code is extended such that up-down anti-symmetric equilibrium can be handled as well as up-down symmetric equilibrium. The orbit of runaway electron is followed using drift Hamiltonian model in Boozer co-ordinates. The analytical model for perturbed magnetic field is introduced to simulate magnetic turbulence during disruption phase. The time variation of canonical angular momentum of relativistic electron in the toroidal direction is analyzed in the case with magnetic island. In addition, Poincare plot of particle orbitis done. The preliminary result indicates that the runaway electron is well confined under magnetic perturbation for ITER parameters.

Oral presentation

Simulation of runaway electron orbit loss in an ITER-like equilibrium

Matsuyama, Akinobu; Yagi, Masatoshi; Kagei, Yasuhiro*

no journal, , 

Relativistic orbit-following code ETC-Rel is developed to study runaway electron dynamics in magnetic turbulence during tokamak disruptions. The code is applied to up-down asymmetric equilibrium like ITER, where relativistic drift equations are formulated on the basis of the Euler-Lagrange equations in Boozer coordinates especially taking into account loop voltage. For ITER-scale machines, since the ratio of poloidal gyroradius to the device size is much smaller than unity, the distortion of electron orbit with respect to the field-line trajectories is negligible. It indicates that enhancement of magnetic stochasticity due to overlapping of magnetic islands is essential for the degradation of runaway electron confinement. Simulations are used to calculate the mean-square displacement of test particles in magnetic turbulence, showing nondiffusive nature of the radial transport of runaway electrons.

Oral presentation

Modeling of runaway electron generation and confinement during tokamak disruption

Matsuyama, Akinobu; Yagi, Masatoshi; Kagei, Yasuhiro*

no journal, , 

no abstracts in English

Oral presentation

Simulation research on transient response in turbulent plasma

Yagi, Masatoshi; Matsuyama, Akinobu; Takizuka, Tomonori*

no journal, , 

no abstracts in English

Oral presentation

Transient plasma response for peripheral density source in resistive ballooning turbulence

Yagi, Masatoshi; Matsuyama, Akinobu; Takizuka, Tomonori*

no journal, , 

no abstracts in English

Oral presentation

Effects of magnetic fluctuation on runaway electron confinement during tokamak disruptions

Matsuyama, Akinobu; Yagi, Masatoshi; Kagei, Yasuhiro*

no journal, , 

no abstracts in English

61 (Records 1-20 displayed on this page)