Stabilization of external modes in tokamaks by resistive walls and plasma rotation

Abstract

It is shown that low n, pressure-driven, external modes in tokamaks can be fully stabilized by resistive walls when the plasma rotates at some fraction of the sound speed. The stabilization depends on toroidal coupling to sound waves and is affected by ion Landau damping. Two-dimensional stability calculations are presented to show the resulting gains in the beta limit.