TILT STABILIZATION BY CYCLING IONS CROSSING MAGNETIC SEPARATRIX IN A FIELD-REVERSED CONFIGURATION

The stabilization of the tilt disruption in a held-reversed configurat ion is investigated by means of a three-dimensional particle simulatio n. The growth rate of tilting instability decreases as the plasma beta value at magnetic separatrix beta(sp) increases, while it is slightly affected by the finite ion Larmor radius parameter (s) over bar and t he hollowness parameter of an equilibrium current profile D for low be ta(sp) and moderately kinetic (2 less than or equal to (s) over bar le ss than or equal to 5) plasmas. It is found that the number flux of io ns crossing the separatrix repeatedly increases with increasing beta(s p) and the crossing motion of ions plays a role in leading to the tilt stabilization by disturbing the unstable tilting motion. (C) 1997 Ame rican Institute of Physics. [S1070-664X(97)02911-X].