Extension of the Newcomb equation into the vacuum for the stability analysis of tokamak edge plasmas

Aiba, Nobuyuki; Tokuda, Shinji; Ishizawa, Tomoko*; Okamoto, Masao*

The formulation for solving numerically the two-dimensional Newcomb equation has been extended to calculate the vacuum energy integral by using a vector potential method. According to this extention, a stability code MARG2D has been adapted, and coded for parallel computing in order to reduce substantially the CPU time. The MARG2D code enables a fast stability analysis of ideal external MHD modes from low to high toroidal mode numbers on the basis of the single physical model, and then the code works as a powerful tool in an integrated simulation where it is combined with transport codes, and also in the analysis of tokamak edge plasma experiments.