Plasma and Fusion Research

Volume 7, 1403070 (2012)

Regular Articles

Low Beta MHD Equilibrium Including a Static Magnetic Island for Reduced MHD Equations in a Straight Heliotron Configuration

Kinya SAITO¹⁾, Katsuji ICHIGUCHI^1,2) and Ryuichi ISHIZAKI^1,2)

1): The Graduate University for Advanced Studies, Toki, Gifu 509-5292, Japan
2): National Institute for Fusion Science, Toki, Gifu 509-5292, Japan

(Received 6 December 2011 / Accepted 18 April 2012 / Published 26 July 2012)

Abstract

Low beta MHD equilibria including static magnetic islands generated by an external field are studied by using a two-step approach. The equilibria correspond to the reduced MHD equations in a straight heliotron configuration. In the first step, a diffusion equation parallel to the field line is solved with the magnetic field fixed for a solution of the pressure constant along field lines. In the second step, the equilibrium equation corresponding to the vorticity equation is solved with the pressure fixed for a solution of the poloidal magnetic flux. The two steps are iterated until the width of the island is converged. The equilibrium pressure profile as a result of the method is locally flat at both the O-point and the X-point of the magnetic island. Effects of a pressure diffusion perpendicular to the field are also studied. In this case, an equilibrium pressure of which the profile is flat at the O-point and steep at the X-point is obtained.

Keywords

static magnetic island, reduced MHD equation, straight heliotron configuration, equilibrium pressure profile, diffusion perpendicular to the field

DOI: 10.1585/pfr.7.1403070

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This paper may be cited as follows:

Kinya SAITO, Katsuji ICHIGUCHI and Ryuichi ISHIZAKI, Plasma Fusion Res. 7, 1403070 (2012).