Current-driven internal kink modes in cylindrical and helicoidal discharges

Abstract

The stability of the internal m=1 kink mode is shown to be very sensitive to small distortions of a circular cylindrical equilibrium. Cylindrical and helicoidal m=2 distortions are destabilizing. Triangular m=3 and quadrangular m=4 distortions provide a means of stabilizing the internal kind mode.