Generation of whistler emissions by injection of hot electrons in the presence of a perpendicular Ac electric field

Abstract

The dispersion for the whistler mode instability in an infinite magnetoplasma in the presence of a perpendicular electric field for a loss cone type distribution function having an anisotropic temperature is obtained. The method of characteristics solutions using the perturbed and unperturbed particle trajectories have been used to determine the perturbed distribution function. Growth rates for various strengths of the loss cone index have been determined. The effect of injection of hot energetic particles of solar wind origin having a positive slope and a loss cone index j=1 has been evaluated. The ac frequency, rather than its magnitude, affects the growth rate and shifts the maxima to a higher or frequency range, modifying the resonance conditions of charged particles. The injection of a higher number of energetic hot electrons affects the growth rate significantly, decreasing the maxima by an order of magnitude and shifting them to a lower frequency or ranges in contrast to cold plasma injection results. This result is of importance in explaining the observed VLF emissions over a wide frequency range.