Cluster boundary layer measurements and optical observations at magnetically conjugate sites
The Cluster spacecraft experienced several boundary layer encounters when flying outbound from the magnetosphere to the magnetosheath in the dusk sector on 14 January 2001. The dayside boundary layer was populated by magnetosheath electrons, but not with quite as high densities as in the magnetoshea...
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ftcopernicus:oai:publications.copernicus.org:angeo34778 2023-05-15T16:29:49+02:00 Cluster boundary layer measurements and optical observations at magnetically conjugate sites Moen, J. Holtet, J. A. Pedersen, A. Lybekk, B. Svenes, K. Oksavik, K. Denig, W. F. Lucek, E. Søraas, F. André, M. 2018-09-27 application/pdf https://doi.org/10.5194/angeo-19-1655-2001 https://angeo.copernicus.org/articles/19/1655/2001/ eng eng doi:10.5194/angeo-19-1655-2001 https://angeo.copernicus.org/articles/19/1655/2001/ eISSN: 1432-0576 Text 2018 ftcopernicus https://doi.org/10.5194/angeo-19-1655-2001 2020-07-20T16:27:53Z The Cluster spacecraft experienced several boundary layer encounters when flying outbound from the magnetosphere to the magnetosheath in the dusk sector on 14 January 2001. The dayside boundary layer was populated by magnetosheath electrons, but not with quite as high densities as in the magnetosheath itself. The Cluster ground track was calculated using the Tsyganenko-96 model which appears to be a strong tool for combining high-altitude satellite and ground observations, given that the solar wind conditions are known. This paper focuses on identifying auroral responses corresponding to boundary layer dynamics observed by Cluster. The first boundary layer encounter studied was a brief visit into a closed LLBL, most likely due to a boundary wave that travelled tailward over the spacecraft. A corresponding equatorward and eastward movement was seen in the post-noon aurora between Greenland and Svalbard. The second boundary encounter was in a high-latitude cusp, and occurred as a consequence of a transient reconfiguration of the cusp. The cusp expanded duskward over the spacecraft into the late post-noon sector. NOAA-12 probed the 16:30 MLT sector of this auroral activity, and measured a 1.4 keV electron beam located poleward of the 30 keV electron-trapping boundary. A sequence of three moving auroral forms emanating from this active region are likely candidates for flux transfer events. The auroral signatures are discussed in relation to earlier observations, and appear to be an example of accelerated electrons/discrete post-noon aurora on open magnetic field lines. Key words. Ionosphere (particle precipitation) Magnetospheric physics (auroral phenomena; magnetopause, cusp and boundary layers) Text Greenland Svalbard Copernicus Publications: E-Journals Greenland Svalbard Annales Geophysicae 19 10/12 1655 1668 |
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Open Polar |
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Copernicus Publications: E-Journals |
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ftcopernicus |
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English |
description |
The Cluster spacecraft experienced several boundary layer encounters when flying outbound from the magnetosphere to the magnetosheath in the dusk sector on 14 January 2001. The dayside boundary layer was populated by magnetosheath electrons, but not with quite as high densities as in the magnetosheath itself. The Cluster ground track was calculated using the Tsyganenko-96 model which appears to be a strong tool for combining high-altitude satellite and ground observations, given that the solar wind conditions are known. This paper focuses on identifying auroral responses corresponding to boundary layer dynamics observed by Cluster. The first boundary layer encounter studied was a brief visit into a closed LLBL, most likely due to a boundary wave that travelled tailward over the spacecraft. A corresponding equatorward and eastward movement was seen in the post-noon aurora between Greenland and Svalbard. The second boundary encounter was in a high-latitude cusp, and occurred as a consequence of a transient reconfiguration of the cusp. The cusp expanded duskward over the spacecraft into the late post-noon sector. NOAA-12 probed the 16:30 MLT sector of this auroral activity, and measured a 1.4 keV electron beam located poleward of the 30 keV electron-trapping boundary. A sequence of three moving auroral forms emanating from this active region are likely candidates for flux transfer events. The auroral signatures are discussed in relation to earlier observations, and appear to be an example of accelerated electrons/discrete post-noon aurora on open magnetic field lines. Key words. Ionosphere (particle precipitation) Magnetospheric physics (auroral phenomena; magnetopause, cusp and boundary layers) |
format |
Text |
author |
Moen, J. Holtet, J. A. Pedersen, A. Lybekk, B. Svenes, K. Oksavik, K. Denig, W. F. Lucek, E. Søraas, F. André, M. |
spellingShingle |
Moen, J. Holtet, J. A. Pedersen, A. Lybekk, B. Svenes, K. Oksavik, K. Denig, W. F. Lucek, E. Søraas, F. André, M. Cluster boundary layer measurements and optical observations at magnetically conjugate sites |
author_facet |
Moen, J. Holtet, J. A. Pedersen, A. Lybekk, B. Svenes, K. Oksavik, K. Denig, W. F. Lucek, E. Søraas, F. André, M. |
author_sort |
Moen, J. |
title |
Cluster boundary layer measurements and optical observations at magnetically conjugate sites |
title_short |
Cluster boundary layer measurements and optical observations at magnetically conjugate sites |
title_full |
Cluster boundary layer measurements and optical observations at magnetically conjugate sites |
title_fullStr |
Cluster boundary layer measurements and optical observations at magnetically conjugate sites |
title_full_unstemmed |
Cluster boundary layer measurements and optical observations at magnetically conjugate sites |
title_sort |
cluster boundary layer measurements and optical observations at magnetically conjugate sites |
publishDate |
2018 |
url |
https://doi.org/10.5194/angeo-19-1655-2001 https://angeo.copernicus.org/articles/19/1655/2001/ |
geographic |
Greenland Svalbard |
geographic_facet |
Greenland Svalbard |
genre |
Greenland Svalbard |
genre_facet |
Greenland Svalbard |
op_source |
eISSN: 1432-0576 |
op_relation |
doi:10.5194/angeo-19-1655-2001 https://angeo.copernicus.org/articles/19/1655/2001/ |
op_doi |
https://doi.org/10.5194/angeo-19-1655-2001 |
container_title |
Annales Geophysicae |
container_volume |
19 |
container_issue |
10/12 |
container_start_page |
1655 |
op_container_end_page |
1668 |
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1766019526648922112 |