Analysis on the relativistic electron precipitation in the midnight sector

Abstract

We analyze the precipitation of relativistic electrons occurring in the midnight sector, defined over 22–02 MLT. In the nightside, electron precipitation is primarily driven either by pitch angle scattering from interactions between electrons and plasma waves or by pitch angle scattering due to the stretching of magnetic field lines (also called “current sheet scattering”). We identified ~400 relativistic electron precipitation events and separated them into wave-driven (REPs) and CSS-driven (CSSs) events. Although REPs tend to occur at slightly lower L shells and CSSs are found at marginally higher L shells, there is not a clear separation in location between these two precipitation types. Furthermore, we show that REPs occur on smaller L shell scales at post-midnight and on wider L shell scales at pre-midnight, suggesting that the wave driver characteristics vary across midnight.First author draf