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dc.contributor.authorSemeter, Joshuaen_US
dc.contributor.authorHunnekuhl, Michaelen_US
dc.contributor.authorMacDonald, Elizabethen_US
dc.contributor.authorHirsch, Michaelen_US
dc.contributor.authorZeller, Neilen_US
dc.contributor.authorChernenkoff, Alexeien_US
dc.contributor.authorWang, Junen_US
dc.date2020-04-17
dc.date.accessioned2021-03-19T13:02:49Z
dc.date.available2021-03-19T13:02:49Z
dc.date.issued2020-12
dc.identifier.citationJoshua Semeter, Michael Hunnekuhl, Elizabeth MacDonald, Michael Hirsch, Neil Zeller, Alexei Chernenkoff, Jun Wang. 2020. "The Mysterious Green Streaks Below STEVE." AGU Advances, Volume 1, Issue 4, https://doi.org/10.1029/2020AV000183
dc.identifier.urihttps://hdl.handle.net/2144/42284
dc.description.abstractStrong thermal emission velocity enhancement (STEVE) is an optical phenomenon of the subauroral ionosphere arising from extreme ion drift speeds. STEVE consists of two distinct components in true‐color imagery: a mauve or whitish arc extended in the magnetic east–west direction and a region of green emission adjacent to the arc, often structured into quasiperiodic columns aligned with the geomagnetic field (the “picket fence”). This work employs high‐resolution imagery by citizen scientists in a critical examination of fine‐scale features within the green emission region. Of particular interest are narrow “streaks” of emission forming underneath field‐aligned picket fence elements in the 100‐ to 110‐km altitude range. The streaks propagate in curved trajectories with dominant direction toward STEVE from the poleward side. The elongation is along the direction of motion, suggesting a drifting point‐like excitation source, with the apparent elongation due to a combination of motion blur and radiative lifetime effects. The cross‐sectional dimension is <1 km, and the cases observed have a duration of ∼20–30 s. The uniform coloration of all STEVE green features in these events suggests a common optical spectrum dominated by the oxygen 557.7‐nm emission line. The source is most likely direct excitation of ambient oxygen by superthermal electrons generated by ionospheric turbulence induced by the extreme electric fields driving STEVE. Some conjectures about causal connections with overlying field‐aligned structures are presented, based on coupling of thermal and gradient‐drift instabilities, with analogues to similar dynamics observed from chemical release and ionospheric heating experiments.en_US
dc.description.urihttps://www.essoar.org/doi/pdf/10.1002/essoar.10502878.1
dc.language.isoen_US
dc.publisherAGUen_US
dc.relation.ispartofAGU Advances
dc.rights©2020. The Authors. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.en_US
dc.rights.urihttp://creativecommons.org/licenses/by/4.0/.
dc.subjectSTEVEen_US
dc.subjectAuroraen_US
dc.subjectIonosphereen_US
dc.subjectTurbulenceen_US
dc.subjectCitizen scienceen_US
dc.subjectAirglowen_US
dc.titleThe mysterious green streaks below STEVEen_US
dc.typeArticleen_US
dc.identifier.doi10.1029/2020AV000183
pubs.elements-sourcemanual-entryen_US
pubs.notesEmbargo: No embargoen_US
pubs.organisational-groupBoston Universityen_US
pubs.organisational-groupBoston University, College of Engineeringen_US
pubs.organisational-groupBoston University, College of Engineering, Department of Electrical & Computer Engineeringen_US
pubs.publication-statusSubmitteden_US
dc.date.online2020-10-01
dc.identifier.orcid0000-0001-7442-6205 (Semeter, Joshua)
dc.identifier.orcid0000-0002-1637-6526 (Hirsch, Michael)
dc.description.oaversionFirst author draft
dc.identifier.mycv554329


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©2020. The Authors. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Except where otherwise noted, this item's license is described as ©2020. The Authors. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.