Excitation of whistler mode instability by high energy electrons in the magnetosphere

Abstract

Propagation of whistler mode waves through magnetospheric plasma characterised by a double Maxwellian velocity distribution function has been considered. The presence of a high energy electron tail in the composite velocity distribution function provides the needed free energy which excites instability mechanism for propagating whistler mode waves. The presence of the parallel or the antiparallel electric field governs the growth/decay rate variation with normalised parameter k ̃ = kV e ω H . These results are found to be different from those reported, which have used other forms of electron velocity distribution functions. The dependence of growth/decay rate on magnetospheric parameters plays an important role in the interpretation of wave features recorded by in-situ measurements. The presence of a fraction of high energy tail electrons penetrating through magnetospheric plasma exhibits significant change in the growth/decay rate of whistler mode waves.