Dynamic evolution of energetic outer zone electrons due to whistler mode chorus based on a realistic density model

Abstract

In this paper, we construct a three‐dimensional realistic plasma trough electron density model (particularly a field‐aligned density variation model) following the previous works. We examine the evolution of energetic electrons in the outer radiation belt at locations L = 4.5 and L = 6.0 with and without incorporation of electron density variation along magnetic field lines. Numerical calculation shows that neglect of the density variation along magnetic field lines generally results in overestimates of relativistic electrons phase space density (PSD) due to an underestimate of the plasma parameter fpe/fce along the field lines. Particularly, the overestimates of PSDs due to neglecting field‐aligned density variation are found to increase with kinetic energy Ek and L increasing. At L = 4.5, maximum overestimates of PSDs over all the pitch angles are found to be by a factor of ∼1.5, 2.1, and 4.7 for energies of 1.0, 2.0, and 3.0 MeV in 2 days. At L = 6.0, maximum overestimates of PSDs over all the pitch angles are found to be by a factor of ∼1.5, 18, and 47 for energies of 1.0, 2.0, and 3.0 MeV in 2 days. This result suggests that incorporation of a field‐aligned density variation model is very important to evaluate cyclotron wave‐particle interaction in the outer radiation belt.