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Physics seminar: STEVE - A new type of upper atmospheric emission and unusual magnetosphere-ionosphere processes

Author: Penny Davenport

Posted on Nov 4, 2019

Category: News and Notices

UNB physics department will host a seminar by Toshi Nishimura, Boston University, on Thursday, Nov. 7, from 1:15 - 2:15 p.m. on "STEVE: A new type of upper atmospheric emission and unusual magnetosphere-ionosphere processes." Join us in IUC Physics/Admin Bldg, Room 204.

“STEVE (strong thermal emission velocity enhancement) was recently discovered as a new type of optical emission in the Earth's upper atmosphere equatorward of the auroral oval. STEVE has become increasingly popular among citizen scientists due to its distinct colors and structures of emission in the night sky, and its occurrence over more populated areas than for typical aurora in the auroral oval. This study addresses two major questions of STEVE: what is the energy source of the STEVE purple or mauve colored arc and green picket fence up in space, and what magnetosphere-ionosphere conditions do control the occurrence of STEVE? Using a set of imaging and satellite observations, this study found that STEVE is connected to fast plasma flows, sharp plasma boundaries and intense waves 25,000 km (15,000 miles) up in space. Photographs taken by citizen scientists have played a key role in finding STEVE and its morphology. Plasma heating due to the fast flows and waves is suggested to drive the mauve colored arc. But this mechanism does not explain the picket fence. We found that energetic particle precipitation drives the picket fence. The picket fence is found to occur in both hemispheres at the same time, supporting that the energy source far up in space feeds energy to both hemispheres. Auroral and magnetotail observations show that location of particle injection and currents controls the occurrence of STEVE.”

Please join us for Colloquium tea in P203 beforehand.

Category: News and Notices

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