Effect of longitudinal electrostatic field on the whistler mode propagation in a warm magneto-ionic medium

Ab&&--The dispersion equation for a whistler mode propagation in a warm plasma, subjected to parallel static electric and magnetic fields, is derived by using a linearized coupled VlasovMaxwell equation. From the derived dispersion equation, the amplitude constant CL and phase constant B of the whistler mode are expressed in terms of static electric field Es, static magnetic field B,, the electron number density N,,, the electron temperature and the wave angular frequency w. The effect of a weak static electric field on the propagation of a whistler mode is investigated in detail; the whistler mode may be amplified or attenuated according to whether E, and B,, are in the same direction or in the opposite direction. The spatial rate of change of the wave amplitude and phase velocity of the whistler mode increase with lEOl in general. For a low-frequency wave propagation, a is directly proportional to E,,, CO, and NO, and inversely proportional to Bo3. A whistler mode propagation in the magnetosphere is also considered. The results of study show that the effects of a static electric field on the propagation characteristic of a whistler mode are likely to be more important in the region of low geomagnetic latitude and high altitude rather than in the high latitude region.