Effect of thermal anisotropy on the loss-cone produced high-frequency quasi-electrostatic ion cyclotron waves in mixed warm-cold plasmas

We show that in the case of generalized loss-cone distribution functions characterized by loss-cone index l, parallel thermal velocity αǁ and perpendicular spread α⊥, sufficiently large anisotropy, (αǁ/α⊥), may stabilize the high-frequency electrostatic ion cyclotron instability. The discussion refers to the oblique propagation and includes also a second, cold, ion component (besides warm isotropic electrons). Electromagnetic corrections to the quasi-electrostatic dispersion relation are also considered. Simple analytical expressions for the growth rates are derived and discussed.