Observations of a Throat Aurora Directly Driven by Magnetosheath High-Speed Jet

Abstract

Throat aurora, characterized as an auroral structure bulging out from equatorward boundary of the auroral oval, has been confirmed to correspond to magnetopause crack. Previous studies suggested that the occurrence of throat aurora is influenced by both magnetospheric internal and external factors. It remains unclear if a single external factor, like a magnetosheath high-speed jet (HSJ), can directly drive throat aurora or not. Through coordinated magnetosheath and ground-based observations, we have established a reliable connection between throat auroras observed on the ground and successive HSJs observed in the magnetosheath, suggesting that HSJ can indeed directly induce throat aurora. Upon further investigation, we found that this HSJ-induced throat aurora exhibited highly dynamic properties with a shorter duration compared to previously reported convection-aligned long-duration throat auroras. These findings suggest the involvement of distinct mechanisms in throat aurora generation, emphasizing the necessity for a comprehensive classification to better comprehend this phenomenon.