Gyroscopic stabilization of the internal kink mode

Toroidal rotation is shown to have a strongly stabilizing effect on the ideal internal kink mode. In the gyroscopically stabilized regime, the internal kink is a neutrally stable discrete eigenmode with a finite rotation velocity relative to the plasma at the resonant surface. In the unstable regime, the mode frequency is equal to the plasma rotation frequency at the resonant surface, so that reconnection will prevent nonlinear saturation.