Multi-instrument ground-based observations of a travelling convection vortices event
A coordinated ground-based observational campaign using the IMAGE magnetometer network, EISCAT radars and optical instruments on Svalbard has made possible detailed studies of a travelling convection vortices (TCV) event on 6 January 1992. Combining the data from these facilities allows us to draw a...
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ftdoajarticles:oai:doaj.org/article:a79a75fb8f1c4612b7024bcd277c90e3 2023-05-15T16:04:35+02:00 Multi-instrument ground-based observations of a travelling convection vortices event H. Lühr M. Lockwood P. E. Sandholt T. L. Hansen T. Moretto https://doaj.org/article/a79a75fb8f1c4612b7024bcd277c90e3 EN eng Copernicus Publications http://www.ann-geophys.net/14/162/1996/angeo-14-162-1996.html https://doaj.org/toc/0992-7689 https://doaj.org/toc/1432-0576 0992-7689 1432-0576 https://doaj.org/article/a79a75fb8f1c4612b7024bcd277c90e3 Annales Geophysicae, Vol 14, Iss 2, Pp 162-181 (0000) Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 article ftdoajarticles 2022-12-30T22:30:10Z A coordinated ground-based observational campaign using the IMAGE magnetometer network, EISCAT radars and optical instruments on Svalbard has made possible detailed studies of a travelling convection vortices (TCV) event on 6 January 1992. Combining the data from these facilities allows us to draw a very detailed picture of the features and dynamics of this TCV event. On the way from the noon to the drawn meridian, the vortices went through a remarkable development. The propagation velocity in the ionosphere increased from 2.5 to 7.4 km s –1 , and the orientation of the major axes of the vortices rotated from being almost parallel to the magnetic meridian near noon to essentially perpendicular at dawn. By combining electric fields obtained by EISCAT and ionospheric currents deduced from magnetic field recordings, conductivities associated with the vortices could be estimated. Contrary to expectations we found higher conductivities below the downward field aligned current (FAC) filament than below the upward directed. Unexpected results also emerged from the optical observations. For most of the time there were no discrete aurora at 557.7 nm associated with the TCVs. Only once did a discrete form appear at the foot of the upward FAC. This aurora subsequently expanded eastward and westward leaving its centre at the same longitude while the TCV continued to travel westward. Also we try to identify the source regions of TCVs in the magnetosphere and discuss possible generation mechanisms. Article in Journal/Newspaper EISCAT Svalbard Directory of Open Access Journals: DOAJ Articles Svalbard |
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 H. Lühr M. Lockwood P. E. Sandholt T. L. Hansen T. Moretto Multi-instrument ground-based observations of a travelling convection vortices event |
topic_facet |
Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 |
description |
A coordinated ground-based observational campaign using the IMAGE magnetometer network, EISCAT radars and optical instruments on Svalbard has made possible detailed studies of a travelling convection vortices (TCV) event on 6 January 1992. Combining the data from these facilities allows us to draw a very detailed picture of the features and dynamics of this TCV event. On the way from the noon to the drawn meridian, the vortices went through a remarkable development. The propagation velocity in the ionosphere increased from 2.5 to 7.4 km s –1 , and the orientation of the major axes of the vortices rotated from being almost parallel to the magnetic meridian near noon to essentially perpendicular at dawn. By combining electric fields obtained by EISCAT and ionospheric currents deduced from magnetic field recordings, conductivities associated with the vortices could be estimated. Contrary to expectations we found higher conductivities below the downward field aligned current (FAC) filament than below the upward directed. Unexpected results also emerged from the optical observations. For most of the time there were no discrete aurora at 557.7 nm associated with the TCVs. Only once did a discrete form appear at the foot of the upward FAC. This aurora subsequently expanded eastward and westward leaving its centre at the same longitude while the TCV continued to travel westward. Also we try to identify the source regions of TCVs in the magnetosphere and discuss possible generation mechanisms. |
format |
Article in Journal/Newspaper |
author |
H. Lühr M. Lockwood P. E. Sandholt T. L. Hansen T. Moretto |
author_facet |
H. Lühr M. Lockwood P. E. Sandholt T. L. Hansen T. Moretto |
author_sort |
H. Lühr |
title |
Multi-instrument ground-based observations of a travelling convection vortices event |
title_short |
Multi-instrument ground-based observations of a travelling convection vortices event |
title_full |
Multi-instrument ground-based observations of a travelling convection vortices event |
title_fullStr |
Multi-instrument ground-based observations of a travelling convection vortices event |
title_full_unstemmed |
Multi-instrument ground-based observations of a travelling convection vortices event |
title_sort |
multi-instrument ground-based observations of a travelling convection vortices event |
publisher |
Copernicus Publications |
url |
https://doaj.org/article/a79a75fb8f1c4612b7024bcd277c90e3 |
geographic |
Svalbard |
geographic_facet |
Svalbard |
genre |
EISCAT Svalbard |
genre_facet |
EISCAT Svalbard |
op_source |
Annales Geophysicae, Vol 14, Iss 2, Pp 162-181 (0000) |
op_relation |
http://www.ann-geophys.net/14/162/1996/angeo-14-162-1996.html https://doaj.org/toc/0992-7689 https://doaj.org/toc/1432-0576 0992-7689 1432-0576 https://doaj.org/article/a79a75fb8f1c4612b7024bcd277c90e3 |
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1766400189807984640 |