Numerical Calculation of MHD Equilibria including Static Magnetic Islands in a Straight Heliotron Configuration by Means of a Field Line Tracing Method

摘要

Magnetohydrodynamics (MHD) equilibria including static magnetic islands for the reduced MHD equations in a straight heliotron plasma are calculated. The equilibria are obtained as the solution of the coupled equations of the constant pressure along each field line and the force balance. The former and the latter equations are solved by means of a field line tracing method and a relaxation method, respectively. There exist two kinds of solutions. One is the equilibrium of which the pressure profile is flat at the O-point and steep at the X-point. In this case, the pressure gradient is discontinuous at the separatrix of the magnetic island. The other is the equilibrium of which the pressure profile is flat at not only the O-point but also the X-point. In the case, the pressure gradient is continuous at the separatrix.