Local Time Dependence of the Loss of Energetic Electrons From the Slot Region of the Radiation Belts

An investigation has been made of the local time morphology of electron (>130 keV) precipitation from the slot region of the radiation belts. Quasi-trapped electrons (hmin < 0) were observed just east of the South Atlantic anomaly at low altitudes (∼800 km) from the satellite 1971-089A. On the average, the fluxes of electrons precipitating in the daytime are greater than those near midnight, consistent with the findings of Vampola et al. In addition, shortly after 0800 hours MLT there is a pronounced increase in the frequency of occurrence of peaks in the energy spectra. These peaks have central energies that decrease rapidly with increasing L value. The data reveal that the electron loss processes are more effective during the daytime than near midnight and that there may be basic differences in the nature of the precipitation mechanisms at the two times.