Neoclassical transport benchmark of global full-f gyrokinetic simulation in stellarator configurations

Matsuoka, Seikichi; Idomura, Yasuhiro; Satake, Shinsuke*

Physics of Plasmas, 25(2), p.022510_1 - 022510_10, 2018/02

https://doi.org/10.1063/1.5010071

Global full-f gyrokinetic simulations, in which the gyrokinetic equation is solved based on the first principle without the scale separation with respect to the plasma distribution function, is attracting much attention in the plasma transport simulation studies. In this work, in order to apply a global full-f gyrokinetic simulation code GT5D to stellarator plasmas with complicated three-dimensional magnetic field configurations, we extend finite difference scheme of GT5D and develop a new interface code which incorporates the three-dimensional magnetic equilibria provided by a standard equilibrium code, VMEC. A series of benchmark calculations are carried out for the numerical verification of GT5D. It is successfully demonstrated that GT5D well reproduces results of a theoretical analysis and another global neoclassical transport code.

Global kinetic simulations of neoclassical toroidal viscosity in low-collisional perturbed tokamak plasmas

Matsuoka, Seikichi; Idomura, Yasuhiro; Satake, Shinsuke*

Physics of Plasmas, 24(10), p.102522_1 - 102522_9, 2017/10

https://doi.org/10.1063/1.5008285

In axisymmetric tokamak plasmas, effects of three-dimensional non-axisymmetric magnetic field perturbations caused by error fields etc. have attracted much attention from the view point of the control of the plasma performance and instabilities. Recent studies pointed out that there exists qualitative discrepancy in predicting the collisional viscosity driven by the perturbation between a theoretical bounce-averaged model and a global kinetic simulation. Clarifying the cause of the discrepancy by understanding the underlying mechanism is a key issue to establish a reliable basis for the NTV predictions. In this work, we perform two different kinds of global kinetic simulations for the NTV. As a result, it is first demonstrated that the discrepancy arises owing to the following two mechanisms related to the global particle orbit; (1) the effective magnitude of the perturbation becomes weak due to the loss of the resonant orbit, and (2) the phase mixing along the orbit arises and generates fine scale structures, resulting the damping of the NTV.

Development of a drift-kinetic simulation code for estimating collisional transport affected by RMPs and radial electric field

Kanno, Ryutaro*; Nunami, Masanori*; Satake, Shinsuke*; Matsuoka, Seikichi; Takamaru, Hisanori*

Contributions to Plasma Physics, 56(6-8), p.592 - 597, 2016/08

https://doi.org/10.1002/ctpp.201610044

A drift-kinetic simulation code is developed for estimating collisional transport in quasi-steady state of toroidal plasma affected by resonant magnetic perturbations and radial electric field. In this paper, validity of the code is confirmed through several test calculations. It is found that radial electron flux is reduced by positive radial-electric field, although radial diffusion of electron is strongly affected by chaotic field-lines under an assumption of zero electric field.

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

http://www.jspf.or.jp/Journal/PDF_JSPF/jspf2016_03/jspf2016_03-157.pdf

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.

Quality and performance of a pseudo-random number generator in massively parallel plasma particle simulations

Matsuoka, Seikichi*; Satake, Shinsuke*; Idomura, Yasuhiro; Imamura, Toshiyuki*

Proceedings of Joint International Conference on Mathematics and Computation, Supercomputing in Nuclear Applications and the Monte Carlo Method (M&C + SNA + MC 2015) (CD-ROM), 13 Pages, 2015/04

The quality and performance of a parallel pseudo-random number generator (PRNG), KMATH_RANDOM, are investigated using a Monte Carlo particle simulation code for the plasma transport. The library is based on Mersenne Twister with jump routines and provides a numerical tool which is suitable and easy-to-use on massively parallel supercomputers such as K-computer. The library enables the particle code to increase the parallelization up to several thousand processes without loosing the quality and performance of the PRNG. As a result, the particle code can use large amounts of random numbers, which results in removing unphysical phenomena caused by a numerical noise.

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

Turbulence spectra, transport, and flows in helical plasmas

Watanabe, Tomohiko*; Nunami, Masanori*; Sugama, Hideo*; Satake, Shinsuke*; Matsuoka, Seikichi*; Ishizawa, Akihiro*; Maeyama, Shinya; Tanaka, Kenji*

Proceedings of 24th IAEA Fusion Energy Conference (FEC 2012) (CD-ROM), 8 Pages, 2012/10

http://www-naweb.iaea.org/napc/physics/FEC/FEC2012/papers/460_TH81.pdf

Singular value decomposition analysis of multichannel electron cyclotron emission signals of tokamak plasma

Isayama, Akihiko; Iwama, Naofumi*; Hosoda, Yosuke*; Satake, Shinsuke*; Isei, Nobuaki; Ishida, Shinichi; Sato, Masayasu

Japanese Journal of Applied Physics, Part 2, 42(3), p.L329 - L331, 2003/03

https://doi.org/10.1143/JJAP.42.L329

no abstracts in English

Full-f gyrokinetic simulations for neoclassical toroidal viscosity in a perturbed tokamak configuration

Matsuoka, Seikichi*; Idomura, Yasuhiro; Satake, Shinsuke*

no journal, , 

http://meetings.aps.org/link/BAPS.2014.DPP.CP8.34

A magnetic field perturbation in tokamak plasmas plays a key role in determining the intrinsic rotation and velocity shear, since even a small perturbation can break the axisymmetry in the toroidal direction and induces the finite neoclassical toroidal viscosity (NTV). A simulation study for the NTV evaluation in an axisymmetric tokamak with a small resonant magnetic field perturbation using the full-f gyrokinetic Eulerian code GT5D is presented. The magnetic field perturbation is included in the particle orbit of GT5D only through the Hamiltonian by replacing the axisymmetric magnetic field with the sum of the axisymmetric field and the perturbation, which enables us to perform GT5D simulations without changing the symplectic structure of the single-particle Lagrangian constructed for the equilibrium (axisymmetric) magnetic field. Numerical results are benchmarked with those obtained by the neoclassical transport code, FORTEC-3D, which solves the drift kinetic equation by Monte Carlo method. The NTV of GT5D with a single-helicity perturbation is found to have a similar peaked profile around the resonant surface as that of FORTEC-3D.

Toroidal rotation modeling 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.

no journal, , 

no abstracts in English