Dynamic evolution of the resistive wall mode with finite wall thickness

Abstract

The effects of wall thickness on the resistive wall mode (RWM) are studied in a slab geometry with and without plasma flow. The wall thickness can have a large effect on both the linear growth rate and the nonlinear saturation level of the RWM for a low flow velocity. The effect of the wall thickness on the RWM becomes much weaker for a high flow velocity. We found that there is an optimum wall thickness that suppresses the linear growth rate. The plasma flow can also help to control the growth of the RWM. The optimum wall thickness is about δ∼ 0.04–0.07, and decreases with increasing plasma flow velocity, but is almost independent of the wall location. The effect of the plasma flow on the saturation level is much weaker than that of the wall thickness because the duration of the linear growth phase increases with increasing flow velocity. Finally, we find that the RWM is completely stabilized in the regime with a large wall thickness.