Auroral ion upflows in the F-region and topside ionosphere
Ion flow along geomagnetic field lines is an important mechanism in the coupling of the magnetosphere-ionosphere system. Over the last 25 years or so, a wealth of satellite and radar observations has revealed the ionosphere as a steady and significant source of magnetospheric plasma. In the auroral...
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ftleicesterunfig:oai:figshare.com:article/10155644 2023-05-15T16:04:28+02:00 Auroral ion upflows in the F-region and topside ionosphere Craig. Foster 1997-01-01T00:00:00Z https://figshare.com/articles/thesis/Auroral_ion_upflows_in_the_F-region_and_topside_ionosphere/10155644 unknown 2381/30651 https://figshare.com/articles/thesis/Auroral_ion_upflows_in_the_F-region_and_topside_ionosphere/10155644 All Rights Reserved Uncategorized IR content Text Thesis 1997 ftleicesterunfig 2021-11-11T19:56:51Z Ion flow along geomagnetic field lines is an important mechanism in the coupling of the magnetosphere-ionosphere system. Over the last 25 years or so, a wealth of satellite and radar observations has revealed the ionosphere as a steady and significant source of magnetospheric plasma. In the auroral ionosphere, field-aligned O+ upflows are often detected with fluxes exceeding those observed at higher altitudes, indicating that the ionosphere actively supplies ions to the magnetosphere. A number of mechanisms, principally associated with disturbed ionospheric conditions, have been proposed to account for ion upflows. This thesis documents a study of ion upflows observed in the auroral F-region and topside ionosphere. The work is based almost exclusively on incoherent scatter measurements from the EISCAT facility.;More than 12 years' UHF Common Programme observations were employed in a study of the variation of upflow characteristics as a function of time, altitude, season and solar and geomagnetic activity. The study was extended in altitude with the inclusion of 5 years' vertical measurement from the EISCAT VHF radar. A quantitative comparison between upflow occurrence and plasma heating events was also performed. In addition, a case study is presented, examining three intervals of transient ion upflow detected during a run of the UK EISCAT Special Programme UFIS. The three events highlight some of the energization processes that can occur at different altitudes to generate field-aligned flow. Finally, a more detailed numerical investigation examined a day-side upflow observed by EISCAT in March, 1992. The event was modelled employing a simple 1-D approximation to the ion momentum-balance equation. The model explored the relative effects of plasma pressure, gravity and neutral wind on the field-parallel ion velocity; it was found that knowledge of the ion composition was necessary for accurate modelling of the observations. Thesis EISCAT University of Leicester: Figshare |
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Uncategorized IR content Craig. Foster Auroral ion upflows in the F-region and topside ionosphere |
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Uncategorized IR content |
description |
Ion flow along geomagnetic field lines is an important mechanism in the coupling of the magnetosphere-ionosphere system. Over the last 25 years or so, a wealth of satellite and radar observations has revealed the ionosphere as a steady and significant source of magnetospheric plasma. In the auroral ionosphere, field-aligned O+ upflows are often detected with fluxes exceeding those observed at higher altitudes, indicating that the ionosphere actively supplies ions to the magnetosphere. A number of mechanisms, principally associated with disturbed ionospheric conditions, have been proposed to account for ion upflows. This thesis documents a study of ion upflows observed in the auroral F-region and topside ionosphere. The work is based almost exclusively on incoherent scatter measurements from the EISCAT facility.;More than 12 years' UHF Common Programme observations were employed in a study of the variation of upflow characteristics as a function of time, altitude, season and solar and geomagnetic activity. The study was extended in altitude with the inclusion of 5 years' vertical measurement from the EISCAT VHF radar. A quantitative comparison between upflow occurrence and plasma heating events was also performed. In addition, a case study is presented, examining three intervals of transient ion upflow detected during a run of the UK EISCAT Special Programme UFIS. The three events highlight some of the energization processes that can occur at different altitudes to generate field-aligned flow. Finally, a more detailed numerical investigation examined a day-side upflow observed by EISCAT in March, 1992. The event was modelled employing a simple 1-D approximation to the ion momentum-balance equation. The model explored the relative effects of plasma pressure, gravity and neutral wind on the field-parallel ion velocity; it was found that knowledge of the ion composition was necessary for accurate modelling of the observations. |
format |
Thesis |
author |
Craig. Foster |
author_facet |
Craig. Foster |
author_sort |
Craig. Foster |
title |
Auroral ion upflows in the F-region and topside ionosphere |
title_short |
Auroral ion upflows in the F-region and topside ionosphere |
title_full |
Auroral ion upflows in the F-region and topside ionosphere |
title_fullStr |
Auroral ion upflows in the F-region and topside ionosphere |
title_full_unstemmed |
Auroral ion upflows in the F-region and topside ionosphere |
title_sort |
auroral ion upflows in the f-region and topside ionosphere |
publishDate |
1997 |
url |
https://figshare.com/articles/thesis/Auroral_ion_upflows_in_the_F-region_and_topside_ionosphere/10155644 |
genre |
EISCAT |
genre_facet |
EISCAT |
op_relation |
2381/30651 https://figshare.com/articles/thesis/Auroral_ion_upflows_in_the_F-region_and_topside_ionosphere/10155644 |
op_rights |
All Rights Reserved |
_version_ |
1766400063029903360 |