Ion cyclotron instability in current-carrying plasmas with anisotropic temperatures

Abstract

The effect of thermal anisotropies on the Drummond-Rosenbiuth two-stream ion cyclotron instability is studied. The properties of the instability are found to be dependent on the ratio of parallel electron temperature to perpendicular ion temperature, T_∥e /T_{⊥ ι} which can alternatively be viewed as the product ofT_∥e /T_{⊥ ι} and the ion anisotropyT_∥e /T_{⊥ ι}The critical drift velocity decreases and the growth rate increases with T_∥e /T_{⊥ ι}. However, the dependence on T_∥e /T_{⊥ ι} becomes less sensitive as this temperature ratio increases, and, in the limit of T_∥e /T_{⊥ ι}>1, the instability becomes independent of the perpendicular temperatures.