Pitch angle dependent resonance energy and growth rates of ELF-VLF waves at low latitudes

Abstract

By solving a quadratic equation obtained from the general first order gyro-resonance interaction condition, pitch angle dependent resonance velocities and resonance energies are calculated for the relativistic energetic resonant electrons at low latitudes. Then, assuming exponentially varying energetic electron fluxes and using the calculated values of resonance velocity and resonance energy, the growth rates for the low latitude ELF and VLF waves are computed. It is found that the growth rate decreases with the increase in pitch angle, the decrease being more rapid and prominent at higher values of the pitch angle and wave frequency.