Model of lifetimes of the outer radiation belt electrons in a realistic magnetic field using realistic chorus wave parameters

摘要

The outer radiation belt electrons in the inner magnetosphere show high variability during the geomagnetically disturbed conditions. Quasi-linear diffusion theory provides both a framework for global prediction of particle loss at different energies and an understanding of the dynamics of different particle populations. It has been recently shown that the pitch angle scattering of electrons due to wave-particle interaction with chorus waves modeled in a realistic magnetic field may be significantly different from those estimated in a dipole model. In this work, we present the lifetimes of 1 keV–2 MeV electrons computed in the Tsyganenko 89 magnetic field model for the night, dawn, prenoon, and postnoon magnetic local time (MLT) sectors for different levels of geomagnetic activity and distances. The lifetimes in the realistic field are also compared to those computed in the dipole model. We develop a realistic chorus lower band and upper band wave models for each MLT sector using the recent statistical studies of wave amplitude, wave normal angle, and wave spectral density distributions as functions of magnetic latitude, distance, and Kp index. The increase of plasma trough density with increasing latitude is also included. The obtained in the Tsyganenko 89 field electron lifetimes are parameterized and can be used in 2-D/3-D/4-D convection and particle tracing codes.