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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ftdoajarticles:oai:doaj.org/article:23103286aa864b2d9dba982f6236b1a8 2023-05-15T16:29:56+02:00 Cluster boundary layer measurements and optical observations at magnetically conjugate sites J. Moen J. A. Holtet A. Pedersen B. Lybekk K. Svenes K. Oksavik W. F. Denig E. Lucek F. Søraas M. André 2001-09-01T00:00:00Z https://doi.org/10.5194/angeo-19-1655-2001 https://doaj.org/article/23103286aa864b2d9dba982f6236b1a8 EN eng Copernicus Publications https://www.ann-geophys.net/19/1655/2001/angeo-19-1655-2001.pdf https://doaj.org/toc/0992-7689 https://doaj.org/toc/1432-0576 doi:10.5194/angeo-19-1655-2001 0992-7689 1432-0576 https://doaj.org/article/23103286aa864b2d9dba982f6236b1a8 Annales Geophysicae, Vol 19, Pp 1655-1668 (2001) Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 article 2001 ftdoajarticles https://doi.org/10.5194/angeo-19-1655-2001 2022-12-31T15:43:16Z 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) Article in Journal/Newspaper Greenland Svalbard Directory of Open Access Journals: DOAJ Articles Greenland Svalbard Annales Geophysicae 19 10/12 1655 1668 |
institution |
Open Polar |
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Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 |
spellingShingle |
Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 J. Moen J. A. Holtet A. Pedersen B. Lybekk K. Svenes K. Oksavik W. F. Denig E. Lucek F. Søraas M. André Cluster boundary layer measurements and optical observations at magnetically conjugate sites |
topic_facet |
Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 |
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 |
Article in Journal/Newspaper |
author |
J. Moen J. A. Holtet A. Pedersen B. Lybekk K. Svenes K. Oksavik W. F. Denig E. Lucek F. Søraas M. André |
author_facet |
J. Moen J. A. Holtet A. Pedersen B. Lybekk K. Svenes K. Oksavik W. F. Denig E. Lucek F. Søraas M. André |
author_sort |
J. Moen |
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 |
publisher |
Copernicus Publications |
publishDate |
2001 |
url |
https://doi.org/10.5194/angeo-19-1655-2001 https://doaj.org/article/23103286aa864b2d9dba982f6236b1a8 |
geographic |
Greenland Svalbard |
geographic_facet |
Greenland Svalbard |
genre |
Greenland Svalbard |
genre_facet |
Greenland Svalbard |
op_source |
Annales Geophysicae, Vol 19, Pp 1655-1668 (2001) |
op_relation |
https://www.ann-geophys.net/19/1655/2001/angeo-19-1655-2001.pdf https://doaj.org/toc/0992-7689 https://doaj.org/toc/1432-0576 doi:10.5194/angeo-19-1655-2001 0992-7689 1432-0576 https://doaj.org/article/23103286aa864b2d9dba982f6236b1a8 |
op_doi |
https://doi.org/10.5194/angeo-19-1655-2001 |
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Annales Geophysicae |
container_volume |
19 |
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10/12 |
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1655 |
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1668 |
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