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 of T ∥e /T ⊥ ι and the ion anisotropy T ∥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.