MHD stability analysis of ideal wall modes for CFETR upgrade phase-I scenario using NIMROD

Abstract

Ideal MHD stability of China Fusion Engineering Test Reactor (CFETR) upgrade phase-I baseline scenario has been evaluated using the initial value code NIMROD. The toroidal mode numbers for n=1-30 have been considered for stability analysis both in single-fluid and two-fluid MHD models. Our calculation rusults show that all modes are found to be unstable with characteristics of edge-localized modes. For n ≤ 13 modes, two-fluid MHD model gives a slightly higher growth rates than single-fluid MHD model, while for n > 13 modes, this trend becomes opposite, which means two-fluid MHD model is needed for high-n mode analysis. In addition, n = 1 − 10 modes are found to be more unstable with increasing wall position and eventually their growth rates approach values in the no-wall limit.