New research published in Geophysical Research Letters investigates in-situ ionospheric plasma measurements from the European Space Agency’s Swarm satellites coincident with ground-based optical measurements of the phenomenon known as “Steve”.
The authors show that Steve is consistently associated with narrow ionospheric flow channels called subauroral ion drifts (SAID). These observations are unusually intense with faster ion velocities, lower plasma densities, and higher electron temperatures than most SAID.
The mechanisms responsible for the optical signature of Steve are currently unclear. However, these results suggest that Steve is associated with extremely hot, narrow, and rapid plasma flow channels.
The research was conducted by William Archer from the Department of Physics and Engineering Physics at the University of Saskatchewan, Canada, and was supported by the ESA Living Planet Fellowship in the frame of the grant titled The ionospheric signature of auroral and subauroral fast flows.
The full results of the study are reported in: W. E. Archer et al. (2019). Steve: The Optical Signature of Intense Subauroral Ion Drifts, Geophysical Research Letters, https://doi.org/10.1029/2019GL082687.
Featured image : Steve rising above Mount Chephren in the Canadian Rockies on May 11, 2019. Photograph by Monika Deviat.