Quasi-electrostatic Whistler Wave Dynamics in Earth’s Radiation Belt

Abstract

Abstract We present a semi-analytical model to study the dynamics of quasi-electrostatic whistler (hereafter, referred to as QEW) waves in Earth’s outer radian belt. QEW wave is a new mode of whistler waves and comes into existence when a whistler wave propagates obliquely close to the resonance cone angle. The equations for self-driven QEW waves and density perturbation are obtained by a fluid model and solved using a high-performance numerical simulation. The wave localizes and therefore generates filaments/or thin sheets obliquely to the ambient magnetic field by ponderomotive effect, which arises due to a QEW wave. These thin sheets become more complex and intense with time and finally saturate when the modulational instability attains a quasi-steady state. To analyze the turbulence from QEW waves in the radiation belt, we present the electric field power spectrum of QEW waves with frequency. The spectrum can be given by the power law having scaling of the order of f − 2.3 at high frequency, i.e., in the dissipation range. The steeper spectrum at higher frequency may result from the energization of charged particles by energy taken from the fluctuations.