Plasma and Fusion Research

Volume 3, S1060 (2008)

Regular Articles


Monte-Carlo Simulation of Neoclassical Transport in Magnetic Islands and Ergodic Regions
Ryutaro KANNO1,2), Masanori NUNAMI3), Shinsuke SATAKE1), Hisanori TAKAMARU4), Yukihiro TOMITA1,2), Keisuke NAKAJIMA2), Masao OKAMOTO4) and Nobuyoshi OHYABU1,2)
1)
National Institute for Fusion Science, Toki 509-5292, Japan
2)
Department of Fusion Science, Graduate University for Advanced Studies, Toki 509-5292, Japan
3)
Institute of Laser Engineering, Osaka University, Suita 565-0871, Japan
4)
Department of Computer Science, Chubu University, Kasugai 487-8501, Japan
(Received 16 November 2007 / Accepted 2 April 2008 / Published 1 August 2008)

Abstract

It is shown in Large Helical Device experiments that transport modeling based on only fluid description is insufficient to express edge transport phenomena in and around a magnetic island with lower collisionality. Furthermore, in recent tokamak experiments, it is found that the so-called stochastic diffusion theory based on “field line diffusion” overestimates the radial energy transport in collisionless edge plasma affected by resonant magnetic perturbations, though the perturbations induce a chaotic behavior in the field lines. These results imply that conventional modeling of edge transport should be reconsidered for a lower collisionality case. A simulation study of neoclassical transport in magnetic islands and ergodic regions is attempted for understanding the fundamental properties of such collisionless edge plasma. By using a drift kinetic equation solver without the assumption of nested flux surfaces (the KEATS code), it is possible to conduct the investigation. In this paper, we report the simulation study of ion transport in the ergodic region, neglecting the effects of an electric field and neutrals. The simulation results are interpreted through the discussion based on statistical studies.


Keywords

collisional transport, edge plasma, chaotic field line, stochastic analysis, diffusion process, δf simulation

DOI: 10.1585/pfr.3.S1060


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This paper may be cited as follows:

Ryutaro KANNO, Masanori NUNAMI, Shinsuke SATAKE, Hisanori TAKAMARU, Yukihiro TOMITA, Keisuke NAKAJIMA, Masao OKAMOTO and Nobuyoshi OHYABU, Plasma Fusion Res. 3, S1060 (2008).