Ideal MHD stability code MARG2D for the analysis of external MHD modes in JT-60U plasma

The MARG2D code has been developed to identify the stability of equilibrium against ideal MHD perturbations.[1] With the property of the two-dimensional Newcomb equation, this code realizes to determine whether the equilibrium is stable or unstable explicitly against a broad n range of ideal MHD modes, including a low-n kink-ballooning mode and a intermediate-n peeling-ballooning mode (1$\le$n$\le$100), where n is the toroidal mode number.[2] Moreover, since this code is developed as a parallel computing code, we can analyze the stability of an equilibrium in short time. The MHD stability of JT-60U plasma will be analyzed in detail with these advantages; in particular, a role of low-n external modes on constraining the achievable plasma pressure, and the property of a peeling-ballooning mode stability that is thought to be responsible for edge localized modes (ELMs) phenomena. Here we present results of recent progresses of the MARG2D code; emphasis is put on detailed code benchmarking results. [1] S. Tokuda et. al., Phys. Plasmas 6, 3012 (1999). [2] N. Aiba et. al., submitted to Plasma Phys. Control. Fusion.