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

Abstract

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 Vlasov-Maxwell equation. From the derived dispersion equation, the amplitude constant a and phase constant β of the whistler mode are expressed in terms of static electric field E 0, static magnetic field B 0, the electron number density N 0, the electron temperature and the wave angular frequency ω. 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 0 and B 0 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 ¦ E 0¦ in general. For a low-frequency wave propagation, a is directly proportional to E 0, ω, and N 0, and inversely proportional to B 0 3. 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.