Effect of transverse inhomogeneous electric field and loss-cone distribution on electrostatic ion-cyclotron instability in the ionosphere

223-233Dispersion relation, resonant energy transferred, growth rate and marginal stability of the electrostatic ion-cyclotron wave with general loss-cone distribution function in low-β homogeneous plasma in the presence of a transverse inhomogeneous electric field are discussed by investigating the trajectories of the particles. The wave is assumed to propagate obliquely to the static magnetic field. The whole plasma is considered to consist of resonant and non-resonant particles. It is assumed that resonant particles participate in energy exchange with the wave, whereas non-resonant particles support the oscillatory motion of the wave. Effects of the steepness of the loss-cone distribution and inhomogeneity in electric field on resonant energy transferred and growth rate of the instability are discussed. It is found that the effect of transverse electric field is to stabilize the wave, whereas the inhomogeneity in electric field acts as a source of free energy for the electrostatic ion-cyclotron wave and enhances the growth rate. Effect of steepness of loss-cone is also to enhance the growth rate. The results are interpreted for the space plasma parameters appropriate to the auroral acceleration region