Velocity shear-related ion upflow in the low-altitude ionosphere
Strong ion upflows with field-aligned velocity above 1000ms were observed by the European Incoherent Scatter (EISCAT) UHF Radar at Tromsø, Norway in the dayside auroral region at heights between 500–600km during the 15 May 1997 magnetic storm. Both the EISCAT observations and the Assimilative Mappin...
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ftdoajarticles:oai:doaj.org/article:17cd311fb51c4c138c661afb3c380f95 2023-05-15T16:04:30+02:00 Velocity shear-related ion upflow in the low-altitude ionosphere H. Liu G. Lu 2004-04-01T00:00:00Z https://doi.org/10.5194/angeo-22-1149-2004 https://doaj.org/article/17cd311fb51c4c138c661afb3c380f95 EN eng Copernicus Publications https://www.ann-geophys.net/22/1149/2004/angeo-22-1149-2004.pdf https://doaj.org/toc/0992-7689 https://doaj.org/toc/1432-0576 doi:10.5194/angeo-22-1149-2004 0992-7689 1432-0576 https://doaj.org/article/17cd311fb51c4c138c661afb3c380f95 Annales Geophysicae, Vol 22, Pp 1149-1153 (2004) Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 article 2004 ftdoajarticles https://doi.org/10.5194/angeo-22-1149-2004 2022-12-30T23:56:38Z Strong ion upflows with field-aligned velocity above 1000ms were observed by the European Incoherent Scatter (EISCAT) UHF Radar at Tromsø, Norway in the dayside auroral region at heights between 500–600km during the 15 May 1997 magnetic storm. Both the EISCAT observations and the Assimilative Mapping of Ionospheric Electrodynamics (AMIE) simulation results show that this event occurred in a region with low Joule heating rate, but with strong velocity shear. During the same period, the electron density and temperature showed no sign of soft particle precipitation, which is consistent with the UVI images from the POLAR satellite, thus excluding possible ion energization through soft particle precipitation. Our simple calculation shows that the velocity shear can provide sufficient energy for the observed ion upflow, thus suggesting shear-driven instabilities as a possible heating mechanism. Key words. Ionosphere, particle acceleration, magnetospheric physics Article in Journal/Newspaper EISCAT Tromsø Directory of Open Access Journals: DOAJ Articles Norway Tromsø Annales Geophysicae 22 4 1149 1153 |
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Open Polar |
collection |
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 H. Liu G. Lu Velocity shear-related ion upflow in the low-altitude ionosphere |
topic_facet |
Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 |
description |
Strong ion upflows with field-aligned velocity above 1000ms were observed by the European Incoherent Scatter (EISCAT) UHF Radar at Tromsø, Norway in the dayside auroral region at heights between 500–600km during the 15 May 1997 magnetic storm. Both the EISCAT observations and the Assimilative Mapping of Ionospheric Electrodynamics (AMIE) simulation results show that this event occurred in a region with low Joule heating rate, but with strong velocity shear. During the same period, the electron density and temperature showed no sign of soft particle precipitation, which is consistent with the UVI images from the POLAR satellite, thus excluding possible ion energization through soft particle precipitation. Our simple calculation shows that the velocity shear can provide sufficient energy for the observed ion upflow, thus suggesting shear-driven instabilities as a possible heating mechanism. Key words. Ionosphere, particle acceleration, magnetospheric physics |
format |
Article in Journal/Newspaper |
author |
H. Liu G. Lu |
author_facet |
H. Liu G. Lu |
author_sort |
H. Liu |
title |
Velocity shear-related ion upflow in the low-altitude ionosphere |
title_short |
Velocity shear-related ion upflow in the low-altitude ionosphere |
title_full |
Velocity shear-related ion upflow in the low-altitude ionosphere |
title_fullStr |
Velocity shear-related ion upflow in the low-altitude ionosphere |
title_full_unstemmed |
Velocity shear-related ion upflow in the low-altitude ionosphere |
title_sort |
velocity shear-related ion upflow in the low-altitude ionosphere |
publisher |
Copernicus Publications |
publishDate |
2004 |
url |
https://doi.org/10.5194/angeo-22-1149-2004 https://doaj.org/article/17cd311fb51c4c138c661afb3c380f95 |
geographic |
Norway Tromsø |
geographic_facet |
Norway Tromsø |
genre |
EISCAT Tromsø |
genre_facet |
EISCAT Tromsø |
op_source |
Annales Geophysicae, Vol 22, Pp 1149-1153 (2004) |
op_relation |
https://www.ann-geophys.net/22/1149/2004/angeo-22-1149-2004.pdf https://doaj.org/toc/0992-7689 https://doaj.org/toc/1432-0576 doi:10.5194/angeo-22-1149-2004 0992-7689 1432-0576 https://doaj.org/article/17cd311fb51c4c138c661afb3c380f95 |
op_doi |
https://doi.org/10.5194/angeo-22-1149-2004 |
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Annales Geophysicae |
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22 |
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4 |
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1149 |
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1153 |
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1766400079839625216 |