Characteristics of fragmented aurora-like emissions (FAEs) observed on Svalbard
This 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...
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ftunivbergen:oai:bora.uib.no:11250/2767703 2023-05-15T15:09:36+02:00 Characteristics of fragmented aurora-like emissions (FAEs) observed on Svalbard Dreyer, Joshua Partamies, Noora Whiter, Daniel Ellingsen, Pål Gunnar Baddeley, Lisa Buchert, Stephan C. 2021 application/pdf https://hdl.handle.net/11250/2767703 https://doi.org/10.5194/angeo-39-277-2021 eng eng Copernicus Publications urn:issn:0992-7689 https://hdl.handle.net/11250/2767703 https://doi.org/10.5194/angeo-39-277-2021 cristin:1917672 Annales Geophysicae. 2021, 39 (2), 277-288. Navngivelse 4.0 Internasjonal http://creativecommons.org/licenses/by/4.0/deed.no Copyright Author(s) 2021 Annales Geophysicae 277-288 39 2 Journal article Peer reviewed 2021 ftunivbergen https://doi.org/10.5194/angeo-39-277-2021 2023-03-14T17:40:47Z This 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. publishedVersion Article in Journal/Newspaper Arctic Longyearbyen Svalbard University of Bergen: Bergen Open Research Archive (BORA-UiB) Arctic Farley ENVELOPE(-152.500,-152.500,-86.583,-86.583) Longyearbyen Norway Svalbard Annales Geophysicae 39 2 277 288 |
institution |
Open Polar |
collection |
University of Bergen: Bergen Open Research Archive (BORA-UiB) |
op_collection_id |
ftunivbergen |
language |
English |
description |
This 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. publishedVersion |
format |
Article in Journal/Newspaper |
author |
Dreyer, Joshua Partamies, Noora Whiter, Daniel Ellingsen, Pål Gunnar Baddeley, Lisa Buchert, Stephan C. |
spellingShingle |
Dreyer, Joshua Partamies, Noora Whiter, Daniel Ellingsen, Pål Gunnar Baddeley, Lisa Buchert, Stephan C. Characteristics of fragmented aurora-like emissions (FAEs) observed on Svalbard |
author_facet |
Dreyer, Joshua Partamies, Noora Whiter, Daniel Ellingsen, Pål Gunnar Baddeley, Lisa Buchert, Stephan C. |
author_sort |
Dreyer, Joshua |
title |
Characteristics of fragmented aurora-like emissions (FAEs) observed on Svalbard |
title_short |
Characteristics of fragmented aurora-like emissions (FAEs) observed on Svalbard |
title_full |
Characteristics of fragmented aurora-like emissions (FAEs) observed on Svalbard |
title_fullStr |
Characteristics of fragmented aurora-like emissions (FAEs) observed on Svalbard |
title_full_unstemmed |
Characteristics of fragmented aurora-like emissions (FAEs) observed on Svalbard |
title_sort |
characteristics of fragmented aurora-like emissions (faes) observed on svalbard |
publisher |
Copernicus Publications |
publishDate |
2021 |
url |
https://hdl.handle.net/11250/2767703 https://doi.org/10.5194/angeo-39-277-2021 |
long_lat |
ENVELOPE(-152.500,-152.500,-86.583,-86.583) |
geographic |
Arctic Farley Longyearbyen Norway Svalbard |
geographic_facet |
Arctic Farley Longyearbyen Norway Svalbard |
genre |
Arctic Longyearbyen Svalbard |
genre_facet |
Arctic Longyearbyen Svalbard |
op_source |
Annales Geophysicae 277-288 39 2 |
op_relation |
urn:issn:0992-7689 https://hdl.handle.net/11250/2767703 https://doi.org/10.5194/angeo-39-277-2021 cristin:1917672 Annales Geophysicae. 2021, 39 (2), 277-288. |
op_rights |
Navngivelse 4.0 Internasjonal http://creativecommons.org/licenses/by/4.0/deed.no Copyright Author(s) 2021 |
op_doi |
https://doi.org/10.5194/angeo-39-277-2021 |
container_title |
Annales Geophysicae |
container_volume |
39 |
container_issue |
2 |
container_start_page |
277 |
op_container_end_page |
288 |
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1766340763463974912 |