Internal kink modes in the ion-kinetic regime

The m=1 kink mode is investigated in the high temperature regime where the width of the singular layer is determined by the mean ion gyroradius. This regime is reached in a number of present-day fusion experiments with strong auxiliary heating. A dispersion relation that contains the full kinetic response of the ions is derived and analyzed. The growth rates are larger than the corresponding ones obtained from fluid theory. Diamagnetic stabilization is weaker than in the fluid case. Ion temperature gradients are shown to be stabilizing at low values of the diamagnetic frequency and destabilizing at large values.