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...
Published in: | Annales Geophysicae |
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Format: | Article in Journal/Newspaper |
Language: | English |
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Uppsala universitet, Institutionen för fysik och astronomi
2021
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Online Access: | http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-440898 https://doi.org/10.5194/angeo-39-277-2021 |
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ftuppsalauniv:oai:DiVA.org:uu-440898 2024-02-11T10:01:36+01:00 Characteristics of fragmented aurora-like emissions (FAEs) observed on Svalbard Dreyer, Joshua Partamies, Noora Whiter, Daniel Ellingsen, Pal G. Baddeley, Lisa Buchert, Stephan 2021 application/pdf http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-440898 https://doi.org/10.5194/angeo-39-277-2021 eng eng Uppsala universitet, Institutionen för fysik och astronomi Uppsala universitet, Institutet för rymdfysik, Uppsalaavdelningen Swedish Inst Space Phys IRF, Space Plasma Phys Grp, Uppsala, Sweden.;Uppsala Univ, Dept Phys & Astron, Uppsala, Sweden. Univ Ctr Svalbard, Dept Arctic Geophys, Longyearbyen, Norway.;Univ Bergen, Birkeland Ctr Space Sci, Bergen, Norway. Univ Southampton, Dept Phys & Astron, Southampton, Hants, England. UiT Arctic Univ Norway, Dept Elect Engn, Narvik, Norway. COPERNICUS GESELLSCHAFT MBH Annales Geophysicae, 0992-7689, 2021, 39:2, s. 277-288 orcid:0000-0003-3038-3359 orcid:0000-0001-7130-232X orcid:0000-0003-2158-6074 http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-440898 doi:10.5194/angeo-39-277-2021 ISI:000626343400001 info:eu-repo/semantics/openAccess ELECTRON-TEMPERATURE AIRGLOW INSTABILITY IONOSPHERE ENERGY N(2)1P SCALE RADAR ASK Fusion Plasma and Space Physics plasma och rymdfysik Article in journal info:eu-repo/semantics/article text 2021 ftuppsalauniv https://doi.org/10.5194/angeo-39-277-2021 2024-01-17T23:32:02Z 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 (N-2; 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. Article in Journal/Newspaper Arctic Longyearbyen Svalbard Uppsala University: Publications (DiVA) Arctic Svalbard Longyearbyen Norway Farley ENVELOPE(-152.500,-152.500,-86.583,-86.583) Annales Geophysicae 39 2 277 288 |
institution |
Open Polar |
collection |
Uppsala University: Publications (DiVA) |
op_collection_id |
ftuppsalauniv |
language |
English |
topic |
ELECTRON-TEMPERATURE AIRGLOW INSTABILITY IONOSPHERE ENERGY N(2)1P SCALE RADAR ASK Fusion Plasma and Space Physics plasma och rymdfysik |
spellingShingle |
ELECTRON-TEMPERATURE AIRGLOW INSTABILITY IONOSPHERE ENERGY N(2)1P SCALE RADAR ASK Fusion Plasma and Space Physics plasma och rymdfysik Dreyer, Joshua Partamies, Noora Whiter, Daniel Ellingsen, Pal G. Baddeley, Lisa Buchert, Stephan Characteristics of fragmented aurora-like emissions (FAEs) observed on Svalbard |
topic_facet |
ELECTRON-TEMPERATURE AIRGLOW INSTABILITY IONOSPHERE ENERGY N(2)1P SCALE RADAR ASK Fusion Plasma and Space Physics plasma och rymdfysik |
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 (N-2; 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. |
format |
Article in Journal/Newspaper |
author |
Dreyer, Joshua Partamies, Noora Whiter, Daniel Ellingsen, Pal G. Baddeley, Lisa Buchert, Stephan |
author_facet |
Dreyer, Joshua Partamies, Noora Whiter, Daniel Ellingsen, Pal G. Baddeley, Lisa Buchert, Stephan |
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 |
Uppsala universitet, Institutionen för fysik och astronomi |
publishDate |
2021 |
url |
http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-440898 https://doi.org/10.5194/angeo-39-277-2021 |
long_lat |
ENVELOPE(-152.500,-152.500,-86.583,-86.583) |
geographic |
Arctic Svalbard Longyearbyen Norway Farley |
geographic_facet |
Arctic Svalbard Longyearbyen Norway Farley |
genre |
Arctic Longyearbyen Svalbard |
genre_facet |
Arctic Longyearbyen Svalbard |
op_relation |
Annales Geophysicae, 0992-7689, 2021, 39:2, s. 277-288 orcid:0000-0003-3038-3359 orcid:0000-0001-7130-232X orcid:0000-0003-2158-6074 http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-440898 doi:10.5194/angeo-39-277-2021 ISI:000626343400001 |
op_rights |
info:eu-repo/semantics/openAccess |
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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1790597397720596480 |