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dc.contributor.authorDreyer, Joshua
dc.contributor.authorPartamies, Noora
dc.contributor.authorWhiter, Daniel
dc.contributor.authorEllingsen, Pål Gunnar
dc.contributor.authorBaddeley, Lisa
dc.contributor.authorBuchert, Stephan C.
dc.date.accessioned2021-06-28T11:33:53Z
dc.date.available2021-06-28T11:33:53Z
dc.date.issued2021-03-04
dc.description.abstractThis study analyses the observations of a new type of small-scale aurora-like feature, which is further referred to as fragmented aurora-like emission(s) (FAEs). An all-sky camera captured these FAEs on three separate occasions in 2015 and 2017 at the Kjell Henriksen Observatory near the arctic town of Longyearbyen, Svalbard, Norway. A total of 305 FAE candidates were identified. They seem to appear in two categories – randomly occurring individual FAEs and wave-like structures with regular spacing between FAEs alongside auroral arcs. FAEs show horizontal sizes typically below 20 km, a lack of field-aligned emission extent, and short lifetimes of less than a minute. Emissions were observed at the 557.7 nm line of atomic oxygen and at 673.0 nm (N2; first positive band system) but not at the 427.8 nm emission of N+2 or the 777.4 nm line of atomic oxygen. This suggests an upper limit to the energy that can be produced by the generating mechanism. Their lack of field-aligned extent indicates a different generation mechanism than for aurorae, which are caused by particle precipitation. Instead, these FAEs could be the result of excitation by thermal ionospheric electrons. FAE observations are seemingly accompanied by elevated electron temperatures between 110–120 km and increased ion temperatures at F-region altitudes. One possible explanation for this is Farley–Buneman instabilities of strong local currents. In the present study, we provide an overview of the observations and discuss their characteristics and potential generation mechanisms.en_US
dc.identifier.citationDreyer, Partamies, Whiter, Ellingsen, Baddeley, Buchert. Characteristics of fragmented aurora-like emissions (FAEs) observed on Svalbard. Annales Geophysicae. 2021;39(2):277-288en_US
dc.identifier.cristinIDFRIDAID 1917672
dc.identifier.doi10.5194/angeo-39-277-2021
dc.identifier.issn0992-7689
dc.identifier.issn1432-0576
dc.identifier.urihttps://hdl.handle.net/10037/21576
dc.language.isoengen_US
dc.publisherEuropean Geosciences Union (EGU)en_US
dc.relation.journalAnnales Geophysicae
dc.relation.projectIDinfo:eu-repo/grantAgreement/NRC/SFF/223252/Norway/Birkeland Center for Space Science/BCSS/en_US
dc.rights.accessRightsopenAccessen_US
dc.rights.holderCopyright 2021 The Author(s)en_US
dc.subjectVDP::Technology: 500::Electrotechnical disciplines: 540en_US
dc.subjectVDP::Teknologi: 500::Elektrotekniske fag: 540en_US
dc.titleCharacteristics of fragmented aurora-like emissions (FAEs) observed on Svalbarden_US
dc.type.versionpublishedVersionen_US
dc.typeJournal articleen_US
dc.typeTidsskriftartikkelen_US
dc.typePeer revieweden_US


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