Plasma and Fusion Research

Volume 3, S1034 (2008)

Regular Articles

Nonlinear Simulation of Collapse Phenomenon in Helical Plasma with a Large Pressure Gradient
Naoki MIZUGUCHI1,2), Yasuhiro SUZUKI1) and Nobuyoshi OHYABU1,2)
1)
National Institute for Fusion Science, Toki 509-5292, Japan
2)
The Graduate University for Advanced Studies (SOKENDAI), Toki 509-5292, Japan
(Received 16 November 2007 / Accepted 26 February 2008 / Published 1 August 2008)

Abstract

Nonlinear magnetohydrodynamics (MHD) simulations are conducted for a helical plasma with a large pressure gradient to investigate the collapse event induced by MHD instabilities. The simulation results show that the ballooning-like instabilities on an intermediate spatial scale induce disordering of structures in the barrier region and a drop in the central pressure. It was revealed that the core pressure fall is related to disordering of the magnetic field structure. The simulation results are compared qualitatively with the experimental observations of the collapse events in the superdense core state of the Large Helical Device (LHD). Compared with our previous simulation studies of similar situations in the spherical tokamak (ST) plasma, the results for the helical cases show milder collapses than those in the ST case.

Keywords

magnetohydrodynamics, collapse, helical system, simulation, superdense core

DOI: 10.1585/pfr.3.S1034

Full Text

PDF format (743Kbytes) PDF Download

References

  • [1] N. Ohyabu, T. Morisaki, S. Masuzaki et al., Phys. Rev. Lett. 97, 55002 (2006).
  • [2] R. Sakamoto et al., Proc. of Joint Conf. 17th Int. Toki Conf. 16th Int. Stellarator/Heliotron Workshop 2007, Oct. 15-19, 2007, Toki, (2007).
  • [3] J. Miyazawa et al., Proc. of Joint Conf. 17th Int. Toki Conf. 16th Int. Stellarator/Heliotron Workshop 2007, Oct. 15-19, 2007, Toki, (2007).
  • [4] K. Hatafuji, T. Hayashi and T. Sato, J. Comp. Phys. 81, 169 (1989).
  • [5] Y. Suzuki, N. Nakajima, K. Watanabe et al., Nucl. Fusion 46, L19 (2006).
  • [6] N. Mizuguchi, R. Khan, N. Nakajima and T. Hayashi, Nucl. Fusion 47, 579 (2007).

This paper may be cited as follows:

Naoki MIZUGUCHI, Yasuhiro SUZUKI and Nobuyoshi OHYABU, Plasma Fusion Res. 3, S1034 (2008).