Electron precipitation characteristics during isolated, compound, and multi-night substorm events
A set of 24 isolated, 46 compound, and 36 multi-night substorm events from the years 2008–2013 have been analysed in this study. Isolated substorm events are defined as single expansion–recovery phase pairs, compound substorms consist of multiple phase pairs, and multi-night substorm events refer to...
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ftntnutrondheimi:oai:ntnuopen.ntnu.no:11250/3001441 2023-05-15T16:13:06+02:00 Electron precipitation characteristics during isolated, compound, and multi-night substorm events Partamies, Noora Tesema, Fasil Bland, Emma Heino, Erkka Tyssøy, Hilde Nesse Kallelid, Erlend Salte 2021 application/pdf https://hdl.handle.net/11250/3001441 https://doi.org/10.5194/angeo-39-69-2021 eng eng European Geosciences Union Norges forskningsråd: 287427 Norges forskningsråd: 223252 Norges forskningsråd: 302040 Annales Geophysicae. 2021, 39 (1), 69-83. urn:issn:0992-7689 https://hdl.handle.net/11250/3001441 https://doi.org/10.5194/angeo-39-69-2021 cristin:1910031 Navngivelse 4.0 Internasjonal http://creativecommons.org/licenses/by/4.0/deed.no CC-BY 69-83 39 Annales Geophysicae 1 Peer reviewed Journal article 2021 ftntnutrondheimi https://doi.org/10.5194/angeo-39-69-2021 2022-07-06T22:39:53Z A set of 24 isolated, 46 compound, and 36 multi-night substorm events from the years 2008–2013 have been analysed in this study. Isolated substorm events are defined as single expansion–recovery phase pairs, compound substorms consist of multiple phase pairs, and multi-night substorm events refer to recurring substorm activity on consecutive nights. Approximately 200 nights of substorm activity observed over Fennoscandian Lapland have been analysed for their magnetic disturbance magnitude and the level of cosmic radio noise absorption. Substorm events were automatically detected from the local electrojet index data and visually categorized. We show that isolated substorms have limited lifetimes and spatial extents as compared to the other substorm types. The average intensity (both in absorption and ground-magnetic deflection) of compound and multi-night substorm events is similar. For multi-night substorm events, the first night is rarely associated with the strongest absorption. Instead, the high-energy electron population needed to cause the strongest absorption builds up over 1–2 additional nights of substorm activity. The non-linear relationship between the absorption and the magnetic deflection at high- and low-activity conditions is also discussed. We further collect in situ particle spectra for expansion and recovery phases to construct median precipitation fluxes at energies from 30 eV up to about 800 keV. In the expansion phases the bulk of the spectra show a local maximum flux in the range of a few keV to 10 keV, while in the recovery phases higher fluxes are seen in the range of tens of keV to hundreds of keV. These findings are discussed in the light of earlier observations of substorm precipitation and their atmospheric effects. publishedVersion Article in Journal/Newspaper Fennoscandian Lapland NTNU Open Archive (Norwegian University of Science and Technology) Annales Geophysicae 39 1 69 83 |
institution |
Open Polar |
collection |
NTNU Open Archive (Norwegian University of Science and Technology) |
op_collection_id |
ftntnutrondheimi |
language |
English |
description |
A set of 24 isolated, 46 compound, and 36 multi-night substorm events from the years 2008–2013 have been analysed in this study. Isolated substorm events are defined as single expansion–recovery phase pairs, compound substorms consist of multiple phase pairs, and multi-night substorm events refer to recurring substorm activity on consecutive nights. Approximately 200 nights of substorm activity observed over Fennoscandian Lapland have been analysed for their magnetic disturbance magnitude and the level of cosmic radio noise absorption. Substorm events were automatically detected from the local electrojet index data and visually categorized. We show that isolated substorms have limited lifetimes and spatial extents as compared to the other substorm types. The average intensity (both in absorption and ground-magnetic deflection) of compound and multi-night substorm events is similar. For multi-night substorm events, the first night is rarely associated with the strongest absorption. Instead, the high-energy electron population needed to cause the strongest absorption builds up over 1–2 additional nights of substorm activity. The non-linear relationship between the absorption and the magnetic deflection at high- and low-activity conditions is also discussed. We further collect in situ particle spectra for expansion and recovery phases to construct median precipitation fluxes at energies from 30 eV up to about 800 keV. In the expansion phases the bulk of the spectra show a local maximum flux in the range of a few keV to 10 keV, while in the recovery phases higher fluxes are seen in the range of tens of keV to hundreds of keV. These findings are discussed in the light of earlier observations of substorm precipitation and their atmospheric effects. publishedVersion |
format |
Article in Journal/Newspaper |
author |
Partamies, Noora Tesema, Fasil Bland, Emma Heino, Erkka Tyssøy, Hilde Nesse Kallelid, Erlend Salte |
spellingShingle |
Partamies, Noora Tesema, Fasil Bland, Emma Heino, Erkka Tyssøy, Hilde Nesse Kallelid, Erlend Salte Electron precipitation characteristics during isolated, compound, and multi-night substorm events |
author_facet |
Partamies, Noora Tesema, Fasil Bland, Emma Heino, Erkka Tyssøy, Hilde Nesse Kallelid, Erlend Salte |
author_sort |
Partamies, Noora |
title |
Electron precipitation characteristics during isolated, compound, and multi-night substorm events |
title_short |
Electron precipitation characteristics during isolated, compound, and multi-night substorm events |
title_full |
Electron precipitation characteristics during isolated, compound, and multi-night substorm events |
title_fullStr |
Electron precipitation characteristics during isolated, compound, and multi-night substorm events |
title_full_unstemmed |
Electron precipitation characteristics during isolated, compound, and multi-night substorm events |
title_sort |
electron precipitation characteristics during isolated, compound, and multi-night substorm events |
publisher |
European Geosciences Union |
publishDate |
2021 |
url |
https://hdl.handle.net/11250/3001441 https://doi.org/10.5194/angeo-39-69-2021 |
genre |
Fennoscandian Lapland |
genre_facet |
Fennoscandian Lapland |
op_source |
69-83 39 Annales Geophysicae 1 |
op_relation |
Norges forskningsråd: 287427 Norges forskningsråd: 223252 Norges forskningsråd: 302040 Annales Geophysicae. 2021, 39 (1), 69-83. urn:issn:0992-7689 https://hdl.handle.net/11250/3001441 https://doi.org/10.5194/angeo-39-69-2021 cristin:1910031 |
op_rights |
Navngivelse 4.0 Internasjonal http://creativecommons.org/licenses/by/4.0/deed.no |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.5194/angeo-39-69-2021 |
container_title |
Annales Geophysicae |
container_volume |
39 |
container_issue |
1 |
container_start_page |
69 |
op_container_end_page |
83 |
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1765998709991014400 |