[Table of Contents]

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

Full Text

PDF format (642Kbytes) PDF Download

References

  • [1] K. Narihara et al., Phys. Rev. Lett. 87, 135002 (2001).
  • [2] N. Ohyabu et al., Phys. Rev. Lett. 88, 055005 (2002).
  • [3] N. Ohyabu et al., Plasma Phys. Control. Fusion 47, 1431 (2005).
  • [4] Y. Nagayama et al., Nucl. Fusion 45, 888 (2005).
  • [5] R. Kanno et al., Nucl. Fusion 45, 588 (2005).
  • [6] A.B. Rechester and M.N. Rosenbluth, Phys. Rev. Lett. 40, 38 (1978).
  • [7] K.H. Burrell et al., Plasma Phys. Control. Fusion 47, B37 (2005).
  • [8] T.E. Evans et al., Nature Phys. 2, 419 (2006).
  • [9] N. Ohyabu et al., Nucl. Fusion 27, 2171 (1987).
  • [10] Ph. Ghendrih et al., Plasma Phys. Control. Fusion 38, 1653 (1996).
  • [11] I. Joseph et al., J. Nucl. Mater. 363-365, 591 (2007).
  • [12] S. Jimbo et al., Nucl. Fusion 45, 1534 (2005).
  • [13] M. Nunami et al., Research Report NIFS Series No. NIFS871 (2007).
  • [14] R. Kanno et al., Transport Modeling of Edge Plasma in an m/n = 1/1 Magnetic Island, to be published in Contributions to Plasma Physics.
  • [15] W.X. Wang et al., Plasma Phys. Control. Fusion 41, 1091 (1999).
  • [16] S. Satake et al., Plasma Fusion Res. 1, 002 (2006).
  • [17] S. Satake et al., Plasma Fusion Res. 3, S1062 (2008).
  • [18] A.H. Boozer and G. Kuo-Petravic, Phys. Fluids B 24, 851 (1981).
  • [19] R. Kanno et al., Plasma Fusion Res. 1, 012 (2006).
  • [20] J. Wesson, Tokamaks 3rd ed. (Oxford Univ. Pr., New York, 2004).
  • [21] A. Komori et al., in Proc. 15th International Conf. on Plasma Physics and Controlled Nuclear Fusion Research 1994, Vol.2 (IAEA, Vienna, 1995) p.773.
  • [22] N. Ohyabu et al., J. Nucl. Mater. 220-222, 298 (1995).
  • [23] A. Komori et al., Fusion Eng. Des. 39-40, 241 (1998).
  • [24] A. Maluckov et al., Physica A 322, 13 (2003).
  • [25] Y. Feng et al., J. Nucl. Mater. 266-269, 812 (1999).
  • [26] A. Runov et al., Nucl. Fusion 44, S74 (2004).
  • [27] B. Øksendal, Stochastic Differential Equations (SpringerVerlag, Berlin Heidelberg, 2003) p.48 and p.149.
  • [28] P.C. Clemmow and J.P. Dougherty, Electrodynamics of Particles and Plasmas (Addison-Wesley, Reading, Mass., 1969).
  • [29] D.R. Nicholson, Introduction to Plasma Theory (John Wiley & Sons, New York, 1983).
  • [30] A. Maluckov et al., Plasma Phys. Control. Fusion 43, 1211 (2001).
  • [31] S.I. Braginskii, in Reviews of Plasma Physics, Vol.1, Ed. M.A. Leontovich (Consultants Bureau, New York, 1965) p.205.

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).