Full wave analysis of the current-driven resistive wall mode including the ferromagnetic wall effects

The effects of ferromagnetic wall on the current-driven resistive wall modes (RWMs) are investigated both analytically and numerically. The dispersion relations (DRs) of the RWMs are derived for a flat q-profile and a spatially varying q-profile including the plasma inertia at the vicinity of the plasma surface. The parameter dependences, such as the wall position and the wall permeability, of the growth rate of RWMs are obtained from the DR and the numerical simulations using a full wave linear stability analysis code TASK/WA. The results show much better agreement than previous DR. The growth rate increases monotonically with the permeability. The critical plasma rotation velocity which is needed to stabilized RWMs is also investigated numerically. The critical velocity also increases almost linearly with the permeability because of the increase in the growth rate