Signatures of the midnight open-closed magnetic field line boundary during balanced dayside and nightside reconnection
The geomagnetic conditions were moderately disturbed (Kp = 2) during magnetic midnight on 10 December 1999, when the Tasman International Geospace Environment Radar (TIGER), a Southern Hemisphere HF SuperDARN radar, observed a persistent, sharp latitudinal decrease (~ 90 km) in spectral width near -...
Published in: | Annales Geophysicae |
---|---|
Main Authors: | , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Copernicus Publications
2002
|
Subjects: | |
Online Access: | https://doi.org/10.5194/angeo-20-1617-2002 https://noa.gwlb.de/receive/cop_mods_00035787 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00035741/angeo-20-1617-2002.pdf https://angeo.copernicus.org/articles/20/1617/2002/angeo-20-1617-2002.pdf |
id |
ftnonlinearchiv:oai:noa.gwlb.de:cop_mods_00035787 |
---|---|
record_format |
openpolar |
spelling |
ftnonlinearchiv:oai:noa.gwlb.de:cop_mods_00035787 2023-05-15T17:09:59+02:00 Signatures of the midnight open-closed magnetic field line boundary during balanced dayside and nightside reconnection Parkinson, M. L. Dyson, P. L. Pinnock, M. Devlin, J. C. Hairston, M. R. Yizengaw, E. Wilkinson, P. J. 2002-10 electronic https://doi.org/10.5194/angeo-20-1617-2002 https://noa.gwlb.de/receive/cop_mods_00035787 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00035741/angeo-20-1617-2002.pdf https://angeo.copernicus.org/articles/20/1617/2002/angeo-20-1617-2002.pdf eng eng Copernicus Publications Annales Geophysicae -- http://www.bibliothek.uni-regensburg.de/ezeit/?1458425 -- https://www.ann-geophys.net/ -- https://www.ann-geophys.net/volumes.html -- http://link.springer.com/journal/585 -- 1432-0576 https://doi.org/10.5194/angeo-20-1617-2002 https://noa.gwlb.de/receive/cop_mods_00035787 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00035741/angeo-20-1617-2002.pdf https://angeo.copernicus.org/articles/20/1617/2002/angeo-20-1617-2002.pdf uneingeschränkt info:eu-repo/semantics/openAccess article Verlagsveröffentlichung article Text doc-type:article 2002 ftnonlinearchiv https://doi.org/10.5194/angeo-20-1617-2002 2022-02-08T22:44:26Z The geomagnetic conditions were moderately disturbed (Kp = 2) during magnetic midnight on 10 December 1999, when the Tasman International Geospace Environment Radar (TIGER), a Southern Hemisphere HF SuperDARN radar, observed a persistent, sharp latitudinal decrease (~ 90 km) in spectral width near - 69°L. The line-of-sight Doppler velocity also rapidly declined across this spectral width boundary (SWB). The region poleward of the SWB was characterized by high spectral widths (>200 m/s), and the start of bursty equatorward and eastward flows (>500 m/s), which rapidly expanded equatorward. The relationships between familiar ionospheric and magnetospheric regions were inferred by comparing TIGER data with spectrograms calculated from precipitating particles measured on board the Defence Meteorology Satellite Program (DMSP) F14 satellite. The high spectral width scatter is often observed, and on this evening it was associated with irregularities forming on the open (but soon to be reconnected) field lines threading the polar cap ionosphere to the southern tail lobe. The region equatorward of the SWB was characterized by very low spectral widths (<50 m/s) and generally slower, more zonal flows (<300 m/s). This kind of scatter is more transient, and was associated with irregularities residing on the closed field lines threading the discrete and diffuse auroral oval to the plasma sheet boundary layer (PSBL) and central plasma sheet (CPS). Hence, the SWB was a reasonable proxy for the open-closed field line boundary, and the equatorward limit of the region, with low spectral width, was probably aligned with the poleward wall of the main ionospheric trough. The SWB was observed to contract poleward and expand equatorward on time scales of ~10 min, much as would be expected during balanced dayside and nightside reconnection. Total electron content (TEC) measurements made at Macquarie Island (- 65°L) and Hobart (- 54°L), and the ionograms recorded at the same stations, as well as at Bundoora (- 49°L), also helped to validate the interpretation. Key words. Ionosphere (auroral ionosphere; electric fields and currents; ionosphere-magnetosphere interactions) Article in Journal/Newspaper Macquarie Island Niedersächsisches Online-Archiv NOA Annales Geophysicae 20 10 1617 1630 |
institution |
Open Polar |
collection |
Niedersächsisches Online-Archiv NOA |
op_collection_id |
ftnonlinearchiv |
language |
English |
topic |
article Verlagsveröffentlichung |
spellingShingle |
article Verlagsveröffentlichung Parkinson, M. L. Dyson, P. L. Pinnock, M. Devlin, J. C. Hairston, M. R. Yizengaw, E. Wilkinson, P. J. Signatures of the midnight open-closed magnetic field line boundary during balanced dayside and nightside reconnection |
topic_facet |
article Verlagsveröffentlichung |
description |
The geomagnetic conditions were moderately disturbed (Kp = 2) during magnetic midnight on 10 December 1999, when the Tasman International Geospace Environment Radar (TIGER), a Southern Hemisphere HF SuperDARN radar, observed a persistent, sharp latitudinal decrease (~ 90 km) in spectral width near - 69°L. The line-of-sight Doppler velocity also rapidly declined across this spectral width boundary (SWB). The region poleward of the SWB was characterized by high spectral widths (>200 m/s), and the start of bursty equatorward and eastward flows (>500 m/s), which rapidly expanded equatorward. The relationships between familiar ionospheric and magnetospheric regions were inferred by comparing TIGER data with spectrograms calculated from precipitating particles measured on board the Defence Meteorology Satellite Program (DMSP) F14 satellite. The high spectral width scatter is often observed, and on this evening it was associated with irregularities forming on the open (but soon to be reconnected) field lines threading the polar cap ionosphere to the southern tail lobe. The region equatorward of the SWB was characterized by very low spectral widths (<50 m/s) and generally slower, more zonal flows (<300 m/s). This kind of scatter is more transient, and was associated with irregularities residing on the closed field lines threading the discrete and diffuse auroral oval to the plasma sheet boundary layer (PSBL) and central plasma sheet (CPS). Hence, the SWB was a reasonable proxy for the open-closed field line boundary, and the equatorward limit of the region, with low spectral width, was probably aligned with the poleward wall of the main ionospheric trough. The SWB was observed to contract poleward and expand equatorward on time scales of ~10 min, much as would be expected during balanced dayside and nightside reconnection. Total electron content (TEC) measurements made at Macquarie Island (- 65°L) and Hobart (- 54°L), and the ionograms recorded at the same stations, as well as at Bundoora (- 49°L), also helped to validate the interpretation. Key words. Ionosphere (auroral ionosphere; electric fields and currents; ionosphere-magnetosphere interactions) |
format |
Article in Journal/Newspaper |
author |
Parkinson, M. L. Dyson, P. L. Pinnock, M. Devlin, J. C. Hairston, M. R. Yizengaw, E. Wilkinson, P. J. |
author_facet |
Parkinson, M. L. Dyson, P. L. Pinnock, M. Devlin, J. C. Hairston, M. R. Yizengaw, E. Wilkinson, P. J. |
author_sort |
Parkinson, M. L. |
title |
Signatures of the midnight open-closed magnetic field line boundary during balanced dayside and nightside reconnection |
title_short |
Signatures of the midnight open-closed magnetic field line boundary during balanced dayside and nightside reconnection |
title_full |
Signatures of the midnight open-closed magnetic field line boundary during balanced dayside and nightside reconnection |
title_fullStr |
Signatures of the midnight open-closed magnetic field line boundary during balanced dayside and nightside reconnection |
title_full_unstemmed |
Signatures of the midnight open-closed magnetic field line boundary during balanced dayside and nightside reconnection |
title_sort |
signatures of the midnight open-closed magnetic field line boundary during balanced dayside and nightside reconnection |
publisher |
Copernicus Publications |
publishDate |
2002 |
url |
https://doi.org/10.5194/angeo-20-1617-2002 https://noa.gwlb.de/receive/cop_mods_00035787 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00035741/angeo-20-1617-2002.pdf https://angeo.copernicus.org/articles/20/1617/2002/angeo-20-1617-2002.pdf |
genre |
Macquarie Island |
genre_facet |
Macquarie Island |
op_relation |
Annales Geophysicae -- http://www.bibliothek.uni-regensburg.de/ezeit/?1458425 -- https://www.ann-geophys.net/ -- https://www.ann-geophys.net/volumes.html -- http://link.springer.com/journal/585 -- 1432-0576 https://doi.org/10.5194/angeo-20-1617-2002 https://noa.gwlb.de/receive/cop_mods_00035787 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00035741/angeo-20-1617-2002.pdf https://angeo.copernicus.org/articles/20/1617/2002/angeo-20-1617-2002.pdf |
op_rights |
uneingeschränkt info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/angeo-20-1617-2002 |
container_title |
Annales Geophysicae |
container_volume |
20 |
container_issue |
10 |
container_start_page |
1617 |
op_container_end_page |
1630 |
_version_ |
1766066372736974848 |