The dynamics and relationships of precipitation, temperature and convection boundaries in the dayside auroral ionosphere
A continuous band of high ion temperature, which persisted for about 8h and zigzagged north-south across more than five degrees in latitude in the dayside (07:00-15:00MLT) auroral ionosphere, was observed by the EISCAT VHF radar on 23 November 1999. Latitudinal gradients in the temperature of the F-...
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Copernicus Publications
2004
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ftnonlinearchiv:oai:noa.gwlb.de:cop_mods_00034862 2023-05-15T16:04:50+02:00 The dynamics and relationships of precipitation, temperature and convection boundaries in the dayside auroral ionosphere Moen, J. Lockwood, M. Oksavik, K. Carlson, H. C. Denig, W. F. van Eyken, A. P. McCrea, I. W. 2004-06 electronic https://doi.org/10.5194/angeo-22-1973-2004 https://noa.gwlb.de/receive/cop_mods_00034862 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00034816/angeo-22-1973-2004.pdf https://angeo.copernicus.org/articles/22/1973/2004/angeo-22-1973-2004.pdf eng eng Copernicus Publications Annales Geophysicae -- http://www.bibliothek.uni-regensburg.de/ezeit/?1458425 -- https://www.ann-geophys.net/ -- https://www.ann-geophys.net/volumes.html -- http://link.springer.com/journal/585 -- 1432-0576 https://doi.org/10.5194/angeo-22-1973-2004 https://noa.gwlb.de/receive/cop_mods_00034862 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00034816/angeo-22-1973-2004.pdf https://angeo.copernicus.org/articles/22/1973/2004/angeo-22-1973-2004.pdf uneingeschränkt info:eu-repo/semantics/openAccess article Verlagsveröffentlichung article Text doc-type:article 2004 ftnonlinearchiv https://doi.org/10.5194/angeo-22-1973-2004 2022-02-08T22:45:02Z A continuous band of high ion temperature, which persisted for about 8h and zigzagged north-south across more than five degrees in latitude in the dayside (07:00-15:00MLT) auroral ionosphere, was observed by the EISCAT VHF radar on 23 November 1999. Latitudinal gradients in the temperature of the F-region electron and ion gases (Te and Ti, respectively) have been compared with concurrent observations of particle precipitation and field-perpendicular convection by DMSP satellites, in order to reveal a physical explanation for the persistent band of high Ti, and to test the potential role of Ti and Te gradients as possible markers for the open-closed field line boundary. The north/south movement of the equatorward Ti boundary was found to be consistent with the contraction/expansion of the polar cap due to an unbalanced dayside and nightside reconnection. Sporadic intensifications in Ti, recurring on ~10-min time scales, indicate that frictional heating was modulated by time-varying reconnection, and the band of high Ti was located on open flux. However, the equatorward Ti boundary was not found to be a close proxy of the open-closed boundary. The closest definable proxy of the open-closed boundary is the magnetosheath electron edge observed by DMSP. Although Te appears to be sensitive to magnetosheath electron fluxes, it is not found to be a suitable parameter for routine tracking of the open-closed boundary, as it involves case dependent analysis of the thermal balance. Finally, we have documented a region of newly-opened sunward convecting flux. This region is situated between the convection reversal boundary and the magnetosheath electron edge defining the open-closed boundary. This is consistent with a delay of several minutes between the arrival of the first (super-Alfvénic) magnetosheath electrons and the response in the ionospheric convection, conveyed to the ionosphere by the interior Alfvén wave. It represents a candidate footprint of the low-latitude boundary mixing layer on sunward convecting open flux. Article in Journal/Newspaper EISCAT Niedersächsisches Online-Archiv NOA Annales Geophysicae 22 6 1973 1987 |
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Niedersächsisches Online-Archiv NOA |
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English |
topic |
article Verlagsveröffentlichung |
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article Verlagsveröffentlichung Moen, J. Lockwood, M. Oksavik, K. Carlson, H. C. Denig, W. F. van Eyken, A. P. McCrea, I. W. The dynamics and relationships of precipitation, temperature and convection boundaries in the dayside auroral ionosphere |
topic_facet |
article Verlagsveröffentlichung |
description |
A continuous band of high ion temperature, which persisted for about 8h and zigzagged north-south across more than five degrees in latitude in the dayside (07:00-15:00MLT) auroral ionosphere, was observed by the EISCAT VHF radar on 23 November 1999. Latitudinal gradients in the temperature of the F-region electron and ion gases (Te and Ti, respectively) have been compared with concurrent observations of particle precipitation and field-perpendicular convection by DMSP satellites, in order to reveal a physical explanation for the persistent band of high Ti, and to test the potential role of Ti and Te gradients as possible markers for the open-closed field line boundary. The north/south movement of the equatorward Ti boundary was found to be consistent with the contraction/expansion of the polar cap due to an unbalanced dayside and nightside reconnection. Sporadic intensifications in Ti, recurring on ~10-min time scales, indicate that frictional heating was modulated by time-varying reconnection, and the band of high Ti was located on open flux. However, the equatorward Ti boundary was not found to be a close proxy of the open-closed boundary. The closest definable proxy of the open-closed boundary is the magnetosheath electron edge observed by DMSP. Although Te appears to be sensitive to magnetosheath electron fluxes, it is not found to be a suitable parameter for routine tracking of the open-closed boundary, as it involves case dependent analysis of the thermal balance. Finally, we have documented a region of newly-opened sunward convecting flux. This region is situated between the convection reversal boundary and the magnetosheath electron edge defining the open-closed boundary. This is consistent with a delay of several minutes between the arrival of the first (super-Alfvénic) magnetosheath electrons and the response in the ionospheric convection, conveyed to the ionosphere by the interior Alfvén wave. It represents a candidate footprint of the low-latitude boundary mixing layer on sunward convecting open flux. |
format |
Article in Journal/Newspaper |
author |
Moen, J. Lockwood, M. Oksavik, K. Carlson, H. C. Denig, W. F. van Eyken, A. P. McCrea, I. W. |
author_facet |
Moen, J. Lockwood, M. Oksavik, K. Carlson, H. C. Denig, W. F. van Eyken, A. P. McCrea, I. W. |
author_sort |
Moen, J. |
title |
The dynamics and relationships of precipitation, temperature and convection boundaries in the dayside auroral ionosphere |
title_short |
The dynamics and relationships of precipitation, temperature and convection boundaries in the dayside auroral ionosphere |
title_full |
The dynamics and relationships of precipitation, temperature and convection boundaries in the dayside auroral ionosphere |
title_fullStr |
The dynamics and relationships of precipitation, temperature and convection boundaries in the dayside auroral ionosphere |
title_full_unstemmed |
The dynamics and relationships of precipitation, temperature and convection boundaries in the dayside auroral ionosphere |
title_sort |
dynamics and relationships of precipitation, temperature and convection boundaries in the dayside auroral ionosphere |
publisher |
Copernicus Publications |
publishDate |
2004 |
url |
https://doi.org/10.5194/angeo-22-1973-2004 https://noa.gwlb.de/receive/cop_mods_00034862 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00034816/angeo-22-1973-2004.pdf https://angeo.copernicus.org/articles/22/1973/2004/angeo-22-1973-2004.pdf |
genre |
EISCAT |
genre_facet |
EISCAT |
op_relation |
Annales Geophysicae -- http://www.bibliothek.uni-regensburg.de/ezeit/?1458425 -- https://www.ann-geophys.net/ -- https://www.ann-geophys.net/volumes.html -- http://link.springer.com/journal/585 -- 1432-0576 https://doi.org/10.5194/angeo-22-1973-2004 https://noa.gwlb.de/receive/cop_mods_00034862 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00034816/angeo-22-1973-2004.pdf https://angeo.copernicus.org/articles/22/1973/2004/angeo-22-1973-2004.pdf |
op_rights |
uneingeschränkt info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/angeo-22-1973-2004 |
container_title |
Annales Geophysicae |
container_volume |
22 |
container_issue |
6 |
container_start_page |
1973 |
op_container_end_page |
1987 |
_version_ |
1766400481693794304 |