Ionospheric convection during the magnetic storm of 20-21 March 1990
We report on the response of high-latitude ionospheric convection during the magnetic storm of March 20-21 1990. IMP-8 measurements of solar wind plasma and interplanetary magnetic field (IMF), ionospheric convection flow measurements from the Wick and Goose Bay coherent radars, EISCAT, Millstone Hi...
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ftdoajarticles:oai:doaj.org/article:59f3df2510bc480e860468889b4662a9 2023-05-15T16:04:49+02:00 Ionospheric convection during the magnetic storm of 20-21 March 1990 J. R. Taylor T. K. Yeoman M. Lester M. J. Buonsanto J. L. Scali J. M. Ruohoniemi J. D. Kelly https://doaj.org/article/59f3df2510bc480e860468889b4662a9 EN eng Copernicus Publications http://www.ann-geophys.net/12/1174/1994/angeo-12-1174-1994.html https://doaj.org/toc/0992-7689 https://doaj.org/toc/1432-0576 0992-7689 1432-0576 https://doaj.org/article/59f3df2510bc480e860468889b4662a9 Annales Geophysicae, Vol 12, Iss 12, Pp 1174-1191 (0000) Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 article ftdoajarticles 2022-12-31T08:47:28Z We report on the response of high-latitude ionospheric convection during the magnetic storm of March 20-21 1990. IMP-8 measurements of solar wind plasma and interplanetary magnetic field (IMF), ionospheric convection flow measurements from the Wick and Goose Bay coherent radars, EISCAT, Millstone Hill and Sondrestrom incoherent radars and three digisondes at Millstone Hill, Goose Bay and Qaanaaq are presented. Two intervals of particular interest have been identified. The first starts with a storm sudden commencement at 2243 UT on March 20 and includes the ionospheric activity in the following 7 h. The response time of the ionospheric convection to the southward turning of the IMF in the dusk to midnight local times is found to be approximately half that measured in a similar study at comparable local times during more normal solar wind conditions. Furthermore, this response time is the same as those previously measured on the dayside. An investigation of the expansion of the polar cap during a substorm growth phase based on Faraday's law suggests that the expansion of the polar cap was nonuniform. A subsequent reconfiguration of the nightside convection pattern was also observed, although it was not possible to distinguish between effects due to possible changes in B y and effects due to substorm activity. The second interval, 1200-2100 UT 21 March 1990, included a southward turning of the IMF which resulted in the B z component becoming -10 nT. The response time on the dayside to this change in the IMF at the magnetopause was approximately 15 min to 30 min which is a factor of ~2 greater than those previously measured at higher latitudes. A movement of the nightside flow reversal, possibly driven by current systems associated with the substorm expansion phases, was observed, implying that the nightside convection pattern can be dominated by substorm activity. Article in Journal/Newspaper EISCAT Qaanaaq Directory of Open Access Journals: DOAJ Articles Qaanaaq ENVELOPE(-69.232,-69.232,77.467,77.467) |
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 J. R. Taylor T. K. Yeoman M. Lester M. J. Buonsanto J. L. Scali J. M. Ruohoniemi J. D. Kelly Ionospheric convection during the magnetic storm of 20-21 March 1990 |
topic_facet |
Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 |
description |
We report on the response of high-latitude ionospheric convection during the magnetic storm of March 20-21 1990. IMP-8 measurements of solar wind plasma and interplanetary magnetic field (IMF), ionospheric convection flow measurements from the Wick and Goose Bay coherent radars, EISCAT, Millstone Hill and Sondrestrom incoherent radars and three digisondes at Millstone Hill, Goose Bay and Qaanaaq are presented. Two intervals of particular interest have been identified. The first starts with a storm sudden commencement at 2243 UT on March 20 and includes the ionospheric activity in the following 7 h. The response time of the ionospheric convection to the southward turning of the IMF in the dusk to midnight local times is found to be approximately half that measured in a similar study at comparable local times during more normal solar wind conditions. Furthermore, this response time is the same as those previously measured on the dayside. An investigation of the expansion of the polar cap during a substorm growth phase based on Faraday's law suggests that the expansion of the polar cap was nonuniform. A subsequent reconfiguration of the nightside convection pattern was also observed, although it was not possible to distinguish between effects due to possible changes in B y and effects due to substorm activity. The second interval, 1200-2100 UT 21 March 1990, included a southward turning of the IMF which resulted in the B z component becoming -10 nT. The response time on the dayside to this change in the IMF at the magnetopause was approximately 15 min to 30 min which is a factor of ~2 greater than those previously measured at higher latitudes. A movement of the nightside flow reversal, possibly driven by current systems associated with the substorm expansion phases, was observed, implying that the nightside convection pattern can be dominated by substorm activity. |
format |
Article in Journal/Newspaper |
author |
J. R. Taylor T. K. Yeoman M. Lester M. J. Buonsanto J. L. Scali J. M. Ruohoniemi J. D. Kelly |
author_facet |
J. R. Taylor T. K. Yeoman M. Lester M. J. Buonsanto J. L. Scali J. M. Ruohoniemi J. D. Kelly |
author_sort |
J. R. Taylor |
title |
Ionospheric convection during the magnetic storm of 20-21 March 1990 |
title_short |
Ionospheric convection during the magnetic storm of 20-21 March 1990 |
title_full |
Ionospheric convection during the magnetic storm of 20-21 March 1990 |
title_fullStr |
Ionospheric convection during the magnetic storm of 20-21 March 1990 |
title_full_unstemmed |
Ionospheric convection during the magnetic storm of 20-21 March 1990 |
title_sort |
ionospheric convection during the magnetic storm of 20-21 march 1990 |
publisher |
Copernicus Publications |
url |
https://doaj.org/article/59f3df2510bc480e860468889b4662a9 |
long_lat |
ENVELOPE(-69.232,-69.232,77.467,77.467) |
geographic |
Qaanaaq |
geographic_facet |
Qaanaaq |
genre |
EISCAT Qaanaaq |
genre_facet |
EISCAT Qaanaaq |
op_source |
Annales Geophysicae, Vol 12, Iss 12, Pp 1174-1191 (0000) |
op_relation |
http://www.ann-geophys.net/12/1174/1994/angeo-12-1174-1994.html https://doaj.org/toc/0992-7689 https://doaj.org/toc/1432-0576 0992-7689 1432-0576 https://doaj.org/article/59f3df2510bc480e860468889b4662a9 |
_version_ |
1766400456040382464 |