Non-ideal effects on ballooning mode stability in the presence of resonant magnetic perturbations

The ideal ballooning mode model in the presence of the externally applied resonant magnetic perturbation (RMP), developed by Bird and Hegna [Nucl. Fusion 53, 013004 (2013)], is extended to include the non-ideal effects, i.e., the finite resistivity and diamagnetic drift effects. Using the eigenvalue equation with the non-ideal effects, a comprehensive analysis is carried out to elucidate the impact of the RMP on ballooning mode stability. Finite resistivity is shown to reduce the line bending stabilization in low to intermediate toroidal mode number (n), resulting in the more peaked growth rate spectrum with respect to n. It is shown that the combination of finite resistivity and the RMP-induced local shear modulation have a strong influence on line bending stabilization, leading to an interesting threshold behavior of the ballooning mode stability. This signifies the importance of the RMP to the line bending stabilization coupled with finite resistivity, as well as the local shear modulation.