Connection of Equatorward‐Extending Auroral Streamers and Their Ground Magnetic Depressions to Radiation Belt Injections

Recent analyses indicate that relativistic electron injections from the tail plasma sheet are a crucial, and maybe dominant, contributor to outer radiation belt enhancement events. This is based on precise examination of flux evolution along the dual Van Allen Probe trajectories, which, when the spacecraft are in appropriate locations, allow confident identification of flux enhancements from injections. These injections result from tail meso‐scale flow bursts, which map to the ionosphere as meso‐scale flow channels having an equatorward flow component corresponding to their earthward flow component within the plasma sheet. These flow channels are observable by ground‐based radars when there is sufficient spatial coverage. However, they can also often be identified from auroral imagers and ground magnetometers, since ionospheric flow channels are associated with auroral streamers and ground magnetic field depressions. We have analyzed three cases having isolated brief time intervals of streamers and injections, one case with multiple such intervals, and one major radiation belt enhancement event. This analysis indicates that when auroral streamers and associated ground magnetic field depressions extend equatorward to radiation belt invariant latitudes, they are associated with injections that result in a net enhancement in radiation electron fluxes. Thus, ground auroral and magnetic field observations have potential for helping verify the connection of flow bursts to radiation belt enhancements and for helping detect such radiation belt injections. Furthermore, this study indicates that radiation belt physics is intimately related to auroral and tail physics via their direct physical association with meso‐scale flow bursts and thus localized magnetotail reconnection.