Some observations of energetic electrons in the outer radiation zone during magnetic bays

Abstract

Changes in the cutoff boundary latitude and flux of electrons Ee > 40 kev in the midnight sector of the outer radiation belt during periods when magnetic bays are in progress are studied in this paper from the data obtained by the University of Iowa satellite Injun 4. From this study, it is observed that (1) the outer-zone flux in the midnight sector increases without any change in the boundary latitude during the expansion phase of a magnetic bay and (2) in addition to the increase in flux, there is also an extension of the boundary to higher latitudes during the recovery phase of a magnetic bay. From these observations, it is suggested that magnetic field line merging may not play a primary role in the production of energetic auroral electrons and that acceleration of particles takes place in the outer zone itself and not far out in the magnetotail.