STEVE is in the house!

Don Hampton and Andy Witteman

Physics Dept./GI UAF

An examination of the Poker Flat all-sky imager (allsky.gi.alaska.edu) from March 29, 2019, showed clear signs of the phenomenon recently discovered by citizen scientists across Canada and Alaska. Called STEVE, originally in homage to the popular cartoon and movie “Over the hedge”, the name is also a reasonably accurate back-ronym for Strong Thermal Emission Velocity Enhancement. Last year I (DH) gave a presentation on the basics of STEVE, as known then and new information on the spectral characteristics as measured by the U. Calgary group (with a UAF build spectrograph) that show that STEVE is not the same as an aurora - specifically the emission in the main portion are not produced by electron impact excitation, as are auroral emissions. To date the documented STEVE events had happened at magnetic latitudes that put them out of reach of most of the optical assets here in Alaska. That changed on March 29th. From 07:45 to 09:30 UT the forms and emissions common in STEVE events were seen in cameras at both Poker Flat and Gakona (HAARP). This offers another opportunity to examine the altitude, location, motion and duration of both the pink/red STEVE emissions as well as the associated green “picket fence” structures. We describe the basics of STEVE again, and will discuss the observations and whatever results from the frantic analyses of this event are done by the time we start talking.