Impact of ULF oscillations in solar wind dynamic pressure on the outer radiation belt electrons

Abstract

This work addresses radial transport of outer radiation belt electrons due to ULF disturbances of geomagnetic field. A new approach to calculating inductive electric field is developed and implemented using a dynamical model of the storm-time geomagnetic field. The approach is used to analyze the effects associated with solar wind dynamic pressure (Pdyn). It is found that Pdyn produces large-scale electric fields with maximum intensity at noon and midnight local time. Derived fields are used in test particle calculations of relativistic electron dynamics. The results show that even moderate oscillations of Pdyn typical for quiet-time magnetosphere can result in rapid electron scattering across the drift shells, which identifies Pdyn as one of the primary mechanisms of radial transport in the belt. Calculations show that electron motion is inconsistent with radial diffusion, and hence a more detailed description is reguired for accurate predictions of electron fluxes in the belt. Copyright 2006 by the American Geophysical Union.