2012 Volume 7 Pages 1403070
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.
