On the relationship between auroral absorption, electrojet currents and plasma convection
This is the publisher’s version/PDF (Published in Annales Geophysicae, an open access journal of the European Geosciences Union) In this study, the relationship between auroral absorption, electrojet currents, and ionospheric plasma convection velocity is investigated using a series of new methods w...
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ftunivtroemsoe:oai:munin.uit.no:10037/2386 2024-06-02T08:05:58+00:00 On the relationship between auroral absorption, electrojet currents and plasma convection Hansen, Truls Lynne Kellerman, A. C. Makarevich, R. A. Honary, F. 2009-02-02 6676316 bytes application/pdf https://hdl.handle.net/10037/2386 eng eng Copernicus Publications on behalf of the European Geosciences Union Annales Geophysicae, 27, 473–486, 2009 0992-7689 https://hdl.handle.net/10037/2386 URN:NBN:no-uit_munin_2136 openAccess VDP::Mathematics and natural science: 400::Physics: 430::Space and plasma physics: 437 Ionosphere Auroral ionosphere Electric fields and currents Particle precipitation VDP::Mathematics and natural science: 400::Physics: 430::Electromagnetism acoustics optics: 434 Journal article Tidsskriftartikkel Peer reviewed 2009 ftunivtroemsoe 2024-05-07T08:42:34Z This is the publisher’s version/PDF (Published in Annales Geophysicae, an open access journal of the European Geosciences Union) In this study, the relationship between auroral absorption, electrojet currents, and ionospheric plasma convection velocity is investigated using a series of new methods where temporal correlations are calculated and analysed for different events and MLT sectors. We employ cosmic noise absorption (CNA) observations obtained by the Imaging Riometer for Ionospheric Studies (IRIS) system in Kilpisj¨arvi, Finland, plasma convection measurements by the European Incoherent Scatter (EISCAT) radar, and estimates of the electrojet currents derived from the Tromsø magnetometer data. The IRIS absorption and EISCAT plasma convection measurements are used as a proxy for the particle precipitation component of the Hall conductance and ionospheric electric field, respectively. It is shown that the electrojet currents are affected by both enhanced conductance and electric field but with the relative importance of these two factors varying with magnetic local time (MLT). The correlation between the current and electric field (absorption) is the highest at 12:00– 15:00MLT (00:00–03:00MLT). It is demonstrated that the electric-field-dominant region is asymmetric with respect to magnetic-noon-midnight meridian extending from 09:00 to 21:00MLT. This may be related to the recently reported absence of mirror-symmetry between the effects of positive and negative IMF By on the high-latitude plasma convection pattern. The conductivity-dominant region is somewhat wider than previously thought extending from 21:00 to 09:00MLT with correlation slowly declining from midnight towards the morning, which is interpreted as being in part due to highenergy electron clouds gradually depleting and drifting from midnight towards the morning sector. The conductivitydominant region is further investigated using the extensiveIRIS riometer and Tromsø magnetometer datasets with results showing a distinct seasonal dependence. ... Article in Journal/Newspaper EISCAT Tromsø University of Tromsø: Munin Open Research Archive Tromsø |
institution |
Open Polar |
collection |
University of Tromsø: Munin Open Research Archive |
op_collection_id |
ftunivtroemsoe |
language |
English |
topic |
VDP::Mathematics and natural science: 400::Physics: 430::Space and plasma physics: 437 Ionosphere Auroral ionosphere Electric fields and currents Particle precipitation VDP::Mathematics and natural science: 400::Physics: 430::Electromagnetism acoustics optics: 434 |
spellingShingle |
VDP::Mathematics and natural science: 400::Physics: 430::Space and plasma physics: 437 Ionosphere Auroral ionosphere Electric fields and currents Particle precipitation VDP::Mathematics and natural science: 400::Physics: 430::Electromagnetism acoustics optics: 434 Hansen, Truls Lynne Kellerman, A. C. Makarevich, R. A. Honary, F. On the relationship between auroral absorption, electrojet currents and plasma convection |
topic_facet |
VDP::Mathematics and natural science: 400::Physics: 430::Space and plasma physics: 437 Ionosphere Auroral ionosphere Electric fields and currents Particle precipitation VDP::Mathematics and natural science: 400::Physics: 430::Electromagnetism acoustics optics: 434 |
description |
This is the publisher’s version/PDF (Published in Annales Geophysicae, an open access journal of the European Geosciences Union) In this study, the relationship between auroral absorption, electrojet currents, and ionospheric plasma convection velocity is investigated using a series of new methods where temporal correlations are calculated and analysed for different events and MLT sectors. We employ cosmic noise absorption (CNA) observations obtained by the Imaging Riometer for Ionospheric Studies (IRIS) system in Kilpisj¨arvi, Finland, plasma convection measurements by the European Incoherent Scatter (EISCAT) radar, and estimates of the electrojet currents derived from the Tromsø magnetometer data. The IRIS absorption and EISCAT plasma convection measurements are used as a proxy for the particle precipitation component of the Hall conductance and ionospheric electric field, respectively. It is shown that the electrojet currents are affected by both enhanced conductance and electric field but with the relative importance of these two factors varying with magnetic local time (MLT). The correlation between the current and electric field (absorption) is the highest at 12:00– 15:00MLT (00:00–03:00MLT). It is demonstrated that the electric-field-dominant region is asymmetric with respect to magnetic-noon-midnight meridian extending from 09:00 to 21:00MLT. This may be related to the recently reported absence of mirror-symmetry between the effects of positive and negative IMF By on the high-latitude plasma convection pattern. The conductivity-dominant region is somewhat wider than previously thought extending from 21:00 to 09:00MLT with correlation slowly declining from midnight towards the morning, which is interpreted as being in part due to highenergy electron clouds gradually depleting and drifting from midnight towards the morning sector. The conductivitydominant region is further investigated using the extensiveIRIS riometer and Tromsø magnetometer datasets with results showing a distinct seasonal dependence. ... |
format |
Article in Journal/Newspaper |
author |
Hansen, Truls Lynne Kellerman, A. C. Makarevich, R. A. Honary, F. |
author_facet |
Hansen, Truls Lynne Kellerman, A. C. Makarevich, R. A. Honary, F. |
author_sort |
Hansen, Truls Lynne |
title |
On the relationship between auroral absorption, electrojet currents and plasma convection |
title_short |
On the relationship between auroral absorption, electrojet currents and plasma convection |
title_full |
On the relationship between auroral absorption, electrojet currents and plasma convection |
title_fullStr |
On the relationship between auroral absorption, electrojet currents and plasma convection |
title_full_unstemmed |
On the relationship between auroral absorption, electrojet currents and plasma convection |
title_sort |
on the relationship between auroral absorption, electrojet currents and plasma convection |
publisher |
Copernicus Publications on behalf of the European Geosciences Union |
publishDate |
2009 |
url |
https://hdl.handle.net/10037/2386 |
geographic |
Tromsø |
geographic_facet |
Tromsø |
genre |
EISCAT Tromsø |
genre_facet |
EISCAT Tromsø |
op_relation |
Annales Geophysicae, 27, 473–486, 2009 0992-7689 https://hdl.handle.net/10037/2386 URN:NBN:no-uit_munin_2136 |
op_rights |
openAccess |
_version_ |
1800750853466882048 |