Solar and seasonal dependence of ion frictional heating
International audience Ion frictional heating constitutes one of the principal mechanisms whereby energy, originating in the solar wind, is deposited into the Earth's ionosphere and ultimately the neutral atmosphere. Common programme observations by the EISCAT UHF radar system, spanning the yea...
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ftinsu:oai:HAL:hal-00316600v1 2023-11-12T04:16:36+01:00 Solar and seasonal dependence of ion frictional heating Davies, J. A. Lester, M. Mccrea, I. W. Radio and Space Plasma Physics Group Leicester (RSPP) University of Leicester EISCAT Group Space Science Division 1999 https://hal.science/hal-00316600 https://hal.science/hal-00316600/document https://hal.science/hal-00316600/file/angeo-17-682-1999.pdf en eng HAL CCSD European Geosciences Union hal-00316600 https://hal.science/hal-00316600 https://hal.science/hal-00316600/document https://hal.science/hal-00316600/file/angeo-17-682-1999.pdf info:eu-repo/semantics/OpenAccess ISSN: 0992-7689 EISSN: 1432-0576 Annales Geophysicae https://hal.science/hal-00316600 Annales Geophysicae, 1999, 17 (5), pp.682-691 [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences info:eu-repo/semantics/article Journal articles 1999 ftinsu 2023-10-25T16:25:34Z International audience Ion frictional heating constitutes one of the principal mechanisms whereby energy, originating in the solar wind, is deposited into the Earth's ionosphere and ultimately the neutral atmosphere. Common programme observations by the EISCAT UHF radar system, spanning the years 1984 to 1995, provide the basis for a comprehensive statistical study of ion frictional heating, results of which are documented in this and a previous paper by the authors. In the present work, the authors demonstrate the solar and seasonal dependence of the universal time distribution of frictional heating, and explain these results with reference to corresponding dependences of the ion velocity. Although EISCAT observes a significant increase in the occurrence of enhanced ion velocities associated with increased solar activity, the latter characterised according to the prevailing 10.7 cm solar flux, this is not reflected to such an extent in the occurrence of frictional heating. It is suggested that this is a consequence of the decreased neutral atmosphere response times associated with active solar conditions, resulting from the higher ionospheric plasma densities present. Seasonal effects on the diurnal distribution of ion frictional heating are well explained by corresponding variations in ionospheric convection, the latter principally a result of geometrical factors. It is noted that, over the entire dataset, the variations in the unperturbed F-region ion temperature, required to implement the identification criterion for ion heating, are highly correlated with model values of thermospheric temperature. Keywords. Ionosphere (auroral ionosphere; ionosphere-atmosphere interactions; plasma temperature and density) Article in Journal/Newspaper EISCAT Institut national des sciences de l'Univers: HAL-INSU |
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Institut national des sciences de l'Univers: HAL-INSU |
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ftinsu |
language |
English |
topic |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
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[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences Davies, J. A. Lester, M. Mccrea, I. W. Solar and seasonal dependence of ion frictional heating |
topic_facet |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
description |
International audience Ion frictional heating constitutes one of the principal mechanisms whereby energy, originating in the solar wind, is deposited into the Earth's ionosphere and ultimately the neutral atmosphere. Common programme observations by the EISCAT UHF radar system, spanning the years 1984 to 1995, provide the basis for a comprehensive statistical study of ion frictional heating, results of which are documented in this and a previous paper by the authors. In the present work, the authors demonstrate the solar and seasonal dependence of the universal time distribution of frictional heating, and explain these results with reference to corresponding dependences of the ion velocity. Although EISCAT observes a significant increase in the occurrence of enhanced ion velocities associated with increased solar activity, the latter characterised according to the prevailing 10.7 cm solar flux, this is not reflected to such an extent in the occurrence of frictional heating. It is suggested that this is a consequence of the decreased neutral atmosphere response times associated with active solar conditions, resulting from the higher ionospheric plasma densities present. Seasonal effects on the diurnal distribution of ion frictional heating are well explained by corresponding variations in ionospheric convection, the latter principally a result of geometrical factors. It is noted that, over the entire dataset, the variations in the unperturbed F-region ion temperature, required to implement the identification criterion for ion heating, are highly correlated with model values of thermospheric temperature. Keywords. Ionosphere (auroral ionosphere; ionosphere-atmosphere interactions; plasma temperature and density) |
author2 |
Radio and Space Plasma Physics Group Leicester (RSPP) University of Leicester EISCAT Group Space Science Division |
format |
Article in Journal/Newspaper |
author |
Davies, J. A. Lester, M. Mccrea, I. W. |
author_facet |
Davies, J. A. Lester, M. Mccrea, I. W. |
author_sort |
Davies, J. A. |
title |
Solar and seasonal dependence of ion frictional heating |
title_short |
Solar and seasonal dependence of ion frictional heating |
title_full |
Solar and seasonal dependence of ion frictional heating |
title_fullStr |
Solar and seasonal dependence of ion frictional heating |
title_full_unstemmed |
Solar and seasonal dependence of ion frictional heating |
title_sort |
solar and seasonal dependence of ion frictional heating |
publisher |
HAL CCSD |
publishDate |
1999 |
url |
https://hal.science/hal-00316600 https://hal.science/hal-00316600/document https://hal.science/hal-00316600/file/angeo-17-682-1999.pdf |
genre |
EISCAT |
genre_facet |
EISCAT |
op_source |
ISSN: 0992-7689 EISSN: 1432-0576 Annales Geophysicae https://hal.science/hal-00316600 Annales Geophysicae, 1999, 17 (5), pp.682-691 |
op_relation |
hal-00316600 https://hal.science/hal-00316600 https://hal.science/hal-00316600/document https://hal.science/hal-00316600/file/angeo-17-682-1999.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1782333665070546944 |