Impact of plasma poloidal rotation on resistive wall mode instability in toroidally rotating plasmas

Aiba, Nobuyuki; Shiraishi, Junya; Tokuda, Shinji*

Rotation effect on the stability of the resistive wall mode (RWM) is investigated in a cylindrical plasma and a toroidal plasma with not only a toroidal rotation but also a poloidal rotation. In the case that a poloidal rotation frequency is not so large, the effect of a poloidal rotation can be treated with the modified toroidal rotation frequency, which is determined by subtracting a toroidal component of the rotation parallel to the magnetic field from the toroidal rotation frequency. This effect of a poloidal rotation on the RWM stability depends on its rotational direction, and when this modified toroidal rotation frequency is larger than the original toroidal rotation frequency, a poloidal rotation enhances the stabilizing effect of a rotation on RWM stability. This result indicates that a poloidal rotation produces a dependence of the critical toroidal rotation frequency for stabilizing RWM on the rotational direction of a toroidal rotation in the same magnetic configuration.