%AGallardo‐Lacourt, Bea [Department of Physics and Astronomy University of Calgary Calgary Alberta Canada]%ANishimura, Y. [Department of Electrical and Computer Engineering and Center for Space Physics Boston University Boston MA USA, Department of Atmospheric and Oceanic Sciences University of California Los Angeles CA USA]%ADonovan, E. [Department of Physics and Astronomy University of Calgary Calgary Alberta Canada]%AGillies, D. [Department of Physics and Astronomy University of Calgary Calgary Alberta Canada]%APerry, G. [Department of Physics and Astronomy University of Calgary Calgary Alberta Canada]%AArcher, W. [Department of Physics and Engineering Physics University of Saskatchewan Saskatoon Saskatchewan Canada]%ANava, O. [Department of Engineering Physics Air Force Institute of Technology Wright‐Patterson Air Force Base OH USA]%ASpanswick, E. [Department of Physics and Astronomy University of Calgary Calgary Alberta Canada]%BJournal Name: Journal of Geophysical Research: Space Physics; Journal Volume: 123; Journal Issue: 11; Related Information: CHORUS Timestamp: 2023-09-02 11:31:50 %D2018%IDOI PREFIX: 10.1029 %JJournal Name: Journal of Geophysical Research: Space Physics; Journal Volume: 123; Journal Issue: 11; Related Information: CHORUS Timestamp: 2023-09-02 11:31:50 %K %MOSTI ID: 10374572 %PMedium: X %TA Statistical Analysis of STEVE %XAbstract

There has been an exciting recent development in auroral research associated with the discovery of a new subauroral phenomenon called STEVE (Strong Thermal Emission Velocity Enhancement). Although STEVE has been documented by amateur night sky watchers for decades, it is as yet an unidentified upper atmosphere phenomenon. Observed first by amateur auroral photographers, STEVE appears as a narrow luminous structure across the night sky over thousands of kilometers in the east‐west direction. In this paper, we present the first statistical analysis of the properties of 28 STEVE events identified using Time History of Events and Macroscale Interactions during Substorms (THEMIS) all‐sky imager and the Redline Emission Geospace Observatory (REGO) database. We find that STEVE occurs about 1 hr after substorm onset at the end of a prolonged expansion phase. On average, theALindex magnitude is larger and the expansion phase has a longer duration for STEVE events compared to subauroral ion drifts or substorms. The average duration for STEVE is about 1 hr, and its latitudinal width is ~20 km, which corresponds to ~¼ of the width of narrow auroral structures like streamers. STEVE typically has an equatorward displacement from its initial location of about 50 km and a longitudinal extent of 2,145 km.

%0Journal Article