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Simulation Study of Ballooning Modes in the Large Helical Device

Yasushi TODO, Noriyoshi NAKAJIMA, Masahiko SATO and Hideaki MIURA

National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292, Japan

(Received 24 December 2009 / Accepted 1 March 2010 / Published 10 December 2010)

Abstract

The magnetohydrodynamic (MHD) simulation code MHD Infrastructure for Plasma Simulation (MIPS) was benchmarked on ballooning instability in the Large Helical Device (LHD) plasma. The results were compared to the results of linear analysis by using the CAS3D code. Both the linear growth rates and the spatial profiles were found to be in good agreement. An extended MHD model with finite ion Larmor radius effects was implemented into the MIPS code. Ballooning instabilities were investigated using the extended MHD model, and the results were compared with those using the MHD model. Ion diamagnetic drift was found to reduce the growth rate of the short-wavelength modes; hence, modes with a diamagnetic drift frequency comparable to the ideal MHD growth rate are the most unstable. The most unstable toroidal mode number of ballooning instability in the LHD is reduced to |n| ≤ 5 for hydrogen plasma with ion number density n_i ≤ 10¹⁹ m⁻³.

Copyright (c) 2010 The Japan Society of Plasma Science and Nuclear Fusion Research

Keywords

ballooning modes, MHD, ion diamagnetic drift, Large Helical Device, computer simulation

DOI: 10.1585/pfr.5.S2062

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References

• [1] R. D. Hazeltine and J. D. Meiss, Plasma Confinement (Addison-Wesley, Redwood City) p.222 (1992).
• [2] H. Miura and N. Nakajima, Nucl. Fusion 50, 054006 (2010).
• [3] K. Harafuji, T. Hayashi and T. Sato, J. Comput. Phys. 81, 169 (1989).
• [4] C. Nührenberg, Phys. Plasmas 6, 137 (1999).
• [5] Y. Todo, J. Plasma Phys. 72, 817 (2006).
• [6] N. Nakajima, S. R. Hudson, C. C. Hegna and Y. Nakamura, Nucl. Fusion 46, 177 (2006).

This paper may be cited as follows:

Yasushi TODO, Noriyoshi NAKAJIMA, Masahiko SATO and Hideaki MIURA, Plasma Fusion Res. 5, S2062 (2010).