Seasonal and solar cycle variations of thermally excited 630.0 nm emissions in the polar ionosphere
Solar cycle and seasonal variations have been found in the occurrence of strong thermally excited 630.0 nm emissions in the polar ionosphere. Measurements from the European Incoherent Scatter Svalbard Radar have been used to derive the thermal emission intensity. Thermally excited emissions have bee...
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Online Access: | http://hdl.handle.net/1956/19258 https://doi.org/10.1029/2018ja025477 |
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ftunivbergen:oai:bora.uib.no:1956/19258 2023-05-15T18:29:42+02:00 Seasonal and solar cycle variations of thermally excited 630.0 nm emissions in the polar ionosphere Kwagala, Norah Kaggwa Oksavik, Kjellmar Lorentzen, Dag Arne Johnsen, Magnar Gullikstad Laundal, Karl Magnus 2018-11-13T12:29:19Z http://hdl.handle.net/1956/19258 https://doi.org/10.1029/2018ja025477 eng eng American Geophysical Union Kwagala NK, Oksavik K, Lorentzen DA, Johnsen MG, Laundal KM. Seasonal and solar cycle variations of thermally excited 630.0 nm emissions in the polar ionosphere. Journal of Geophysical Research - Space Physics. 2018:1-11 2169-9402 2169-9380 http://hdl.handle.net/1956/19258 https://doi.org/10.1029/2018ja025477 1602320 CC BY-NC-ND http://creativecommons.org/licenses/by-nc-nd/4.0/ Copyright The Author(s) 2018 CC-BY-NC-ND Journal of Geophysical Research - Space Physics thermal excitation thermally excited emissions polar ionosphere ESR 630.0 nm aurora Peer reviewed Journal article 2018 ftunivbergen https://doi.org/10.1029/2018ja025477 2020-10-28T23:56:06Z Solar cycle and seasonal variations have been found in the occurrence of strong thermally excited 630.0 nm emissions in the polar ionosphere. Measurements from the European Incoherent Scatter Svalbard Radar have been used to derive the thermal emission intensity. Thermally excited emissions have been found to maximize at solar maximum with peak occurrence rate of ∼40% compared to ∼2% at solar minimum. These emissions also have the highest occurrence in equinox and the lowest occurrence rate in summer and winter. There is an equinoctial asymmetry in the occurrence rate which reverses with the solar cycle. This equinoctial asymmetry is attributed to variations of the solar wind‐magnetosphere coupling arising from the Russell‐McPherron effect. The occurrence rate of thermal excitation emission on the dayside, at Svalbard, has been found to be higher in autumn than spring at solar maximum and the reverse at solar minimum. Enhanced electron temperatures characterize the strong thermal component for solar minimum and winter, whereas enhanced electron densities characterize the thermal component for solar maximum. The results point to solar wind‐magnetosphere‐ionosphere coupling as the dominant controlling process. publishedVersion Article in Journal/Newspaper Svalbard University of Bergen: Bergen Open Research Archive (BORA-UiB) Svalbard Journal of Geophysical Research: Space Physics 123 8 7029 7039 |
institution |
Open Polar |
collection |
University of Bergen: Bergen Open Research Archive (BORA-UiB) |
op_collection_id |
ftunivbergen |
language |
English |
topic |
thermal excitation thermally excited emissions polar ionosphere ESR 630.0 nm aurora |
spellingShingle |
thermal excitation thermally excited emissions polar ionosphere ESR 630.0 nm aurora Kwagala, Norah Kaggwa Oksavik, Kjellmar Lorentzen, Dag Arne Johnsen, Magnar Gullikstad Laundal, Karl Magnus Seasonal and solar cycle variations of thermally excited 630.0 nm emissions in the polar ionosphere |
topic_facet |
thermal excitation thermally excited emissions polar ionosphere ESR 630.0 nm aurora |
description |
Solar cycle and seasonal variations have been found in the occurrence of strong thermally excited 630.0 nm emissions in the polar ionosphere. Measurements from the European Incoherent Scatter Svalbard Radar have been used to derive the thermal emission intensity. Thermally excited emissions have been found to maximize at solar maximum with peak occurrence rate of ∼40% compared to ∼2% at solar minimum. These emissions also have the highest occurrence in equinox and the lowest occurrence rate in summer and winter. There is an equinoctial asymmetry in the occurrence rate which reverses with the solar cycle. This equinoctial asymmetry is attributed to variations of the solar wind‐magnetosphere coupling arising from the Russell‐McPherron effect. The occurrence rate of thermal excitation emission on the dayside, at Svalbard, has been found to be higher in autumn than spring at solar maximum and the reverse at solar minimum. Enhanced electron temperatures characterize the strong thermal component for solar minimum and winter, whereas enhanced electron densities characterize the thermal component for solar maximum. The results point to solar wind‐magnetosphere‐ionosphere coupling as the dominant controlling process. publishedVersion |
format |
Article in Journal/Newspaper |
author |
Kwagala, Norah Kaggwa Oksavik, Kjellmar Lorentzen, Dag Arne Johnsen, Magnar Gullikstad Laundal, Karl Magnus |
author_facet |
Kwagala, Norah Kaggwa Oksavik, Kjellmar Lorentzen, Dag Arne Johnsen, Magnar Gullikstad Laundal, Karl Magnus |
author_sort |
Kwagala, Norah Kaggwa |
title |
Seasonal and solar cycle variations of thermally excited 630.0 nm emissions in the polar ionosphere |
title_short |
Seasonal and solar cycle variations of thermally excited 630.0 nm emissions in the polar ionosphere |
title_full |
Seasonal and solar cycle variations of thermally excited 630.0 nm emissions in the polar ionosphere |
title_fullStr |
Seasonal and solar cycle variations of thermally excited 630.0 nm emissions in the polar ionosphere |
title_full_unstemmed |
Seasonal and solar cycle variations of thermally excited 630.0 nm emissions in the polar ionosphere |
title_sort |
seasonal and solar cycle variations of thermally excited 630.0 nm emissions in the polar ionosphere |
publisher |
American Geophysical Union |
publishDate |
2018 |
url |
http://hdl.handle.net/1956/19258 https://doi.org/10.1029/2018ja025477 |
geographic |
Svalbard |
geographic_facet |
Svalbard |
genre |
Svalbard |
genre_facet |
Svalbard |
op_source |
Journal of Geophysical Research - Space Physics |
op_relation |
Kwagala NK, Oksavik K, Lorentzen DA, Johnsen MG, Laundal KM. Seasonal and solar cycle variations of thermally excited 630.0 nm emissions in the polar ionosphere. Journal of Geophysical Research - Space Physics. 2018:1-11 2169-9402 2169-9380 http://hdl.handle.net/1956/19258 https://doi.org/10.1029/2018ja025477 1602320 |
op_rights |
CC BY-NC-ND http://creativecommons.org/licenses/by-nc-nd/4.0/ Copyright The Author(s) 2018 |
op_rightsnorm |
CC-BY-NC-ND |
op_doi |
https://doi.org/10.1029/2018ja025477 |
container_title |
Journal of Geophysical Research: Space Physics |
container_volume |
123 |
container_issue |
8 |
container_start_page |
7029 |
op_container_end_page |
7039 |
_version_ |
1766213017950748672 |