Tilt stabilization by cycling ions crossing magnetic separatrix in a field-reversed configuration

Abstract

The stabilization of the tilt disruption in a field-reversed configuration is investigated by means of a three-dimensional particle simulation. The growth rate of tilting instability decreases as the plasma beta value at magnetic separatrix βsp increases, while it is slightly affected by the finite ion Larmor radius parameter s̄ and the hollowness parameter of an equilibrium current profile D for low βsp and moderately kinetic (2⩽s̄⩽5) plasmas. It is found that the number flux of ions crossing the separatrix repeatedly increases with increasing βsp and the crossing motion of ions plays a role in leading to the tilt stabilization by disturbing the unstable tilting motion.