On the relationship between auroral absorption, electrojet currents and plasma convection
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 (C...
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ftdoajarticles:oai:doaj.org/article:b9d44cb6a8d04ece9e5d81733dc95cc6 2023-05-15T16:04:39+02:00 On the relationship between auroral absorption, electrojet currents and plasma convection A. C. Kellerman R. A. Makarevich F. Honary T. L. Hansen 2009-02-01T00:00:00Z https://doi.org/10.5194/angeo-27-473-2009 https://doaj.org/article/b9d44cb6a8d04ece9e5d81733dc95cc6 EN eng Copernicus Publications https://www.ann-geophys.net/27/473/2009/angeo-27-473-2009.pdf https://doaj.org/toc/0992-7689 https://doaj.org/toc/1432-0576 doi:10.5194/angeo-27-473-2009 0992-7689 1432-0576 https://doaj.org/article/b9d44cb6a8d04ece9e5d81733dc95cc6 Annales Geophysicae, Vol 27, Pp 473-486 (2009) Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 article 2009 ftdoajarticles https://doi.org/10.5194/angeo-27-473-2009 2022-12-30T22:41:01Z 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 Kilpisjärvi, 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 12:00–15:00 MLT (00:00–03:00 MLT). It is demonstrated that the electric-field-dominant region is asymmetric with respect to magnetic-noon-midnight meridian extending from 09:00 to 21:00 MLT. This may be related to the recently reported absence of mirror-symmetry between the effects of positive and negative IMF B y on the high-latitude plasma convection pattern. The conductivity-dominant region is somewhat wider than previously thought extending from 21:00 to 09:00 MLT with correlation slowly declining from midnight towards the morning, which is interpreted as being in part due to high-energy electron clouds gradually depleting and drifting from midnight towards the morning sector. The conductivity-dominant region is further investigated using the extensive IRIS riometer and Tromsø magnetometer datasets with results showing a distinct seasonal dependence. The region of high current-absorption correlation extends from 21:00 to 06:00 MLT near both equinoxes, however, it is narrower ... Article in Journal/Newspaper EISCAT Kilpisjärvi Tromsø Directory of Open Access Journals: DOAJ Articles Kilpisjärvi ENVELOPE(20.767,20.767,69.034,69.034) Tromsø Annales Geophysicae 27 2 473 486 |
institution |
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 A. C. Kellerman R. A. Makarevich F. Honary T. L. Hansen On the relationship between auroral absorption, electrojet currents and plasma convection |
topic_facet |
Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 |
description |
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 Kilpisjärvi, 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 12:00–15:00 MLT (00:00–03:00 MLT). It is demonstrated that the electric-field-dominant region is asymmetric with respect to magnetic-noon-midnight meridian extending from 09:00 to 21:00 MLT. This may be related to the recently reported absence of mirror-symmetry between the effects of positive and negative IMF B y on the high-latitude plasma convection pattern. The conductivity-dominant region is somewhat wider than previously thought extending from 21:00 to 09:00 MLT with correlation slowly declining from midnight towards the morning, which is interpreted as being in part due to high-energy electron clouds gradually depleting and drifting from midnight towards the morning sector. The conductivity-dominant region is further investigated using the extensive IRIS riometer and Tromsø magnetometer datasets with results showing a distinct seasonal dependence. The region of high current-absorption correlation extends from 21:00 to 06:00 MLT near both equinoxes, however, it is narrower ... |
format |
Article in Journal/Newspaper |
author |
A. C. Kellerman R. A. Makarevich F. Honary T. L. Hansen |
author_facet |
A. C. Kellerman R. A. Makarevich F. Honary T. L. Hansen |
author_sort |
A. C. Kellerman |
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 |
publishDate |
2009 |
url |
https://doi.org/10.5194/angeo-27-473-2009 https://doaj.org/article/b9d44cb6a8d04ece9e5d81733dc95cc6 |
long_lat |
ENVELOPE(20.767,20.767,69.034,69.034) |
geographic |
Kilpisjärvi Tromsø |
geographic_facet |
Kilpisjärvi Tromsø |
genre |
EISCAT Kilpisjärvi Tromsø |
genre_facet |
EISCAT Kilpisjärvi Tromsø |
op_source |
Annales Geophysicae, Vol 27, Pp 473-486 (2009) |
op_relation |
https://www.ann-geophys.net/27/473/2009/angeo-27-473-2009.pdf https://doaj.org/toc/0992-7689 https://doaj.org/toc/1432-0576 doi:10.5194/angeo-27-473-2009 0992-7689 1432-0576 https://doaj.org/article/b9d44cb6a8d04ece9e5d81733dc95cc6 |
op_doi |
https://doi.org/10.5194/angeo-27-473-2009 |
container_title |
Annales Geophysicae |
container_volume |
27 |
container_issue |
2 |
container_start_page |
473 |
op_container_end_page |
486 |
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1766400257816526848 |