Signatures of the midnight open-closed magnetic field line boundary during balanced dayside and nightside reconnection
International audience The geomagnetic conditions were moderately disturbed ( K p = 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)...
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ftinsu:oai:HAL:hal-00317180v1 2023-11-12T04:20:49+01:00 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. Department of Physics Victoria La Trobe University Melbourne British Antarctic Survey (BAS) Natural Environment Research Council (NERC) Department of Electronic Engineering Australia William B. Hanson Center for Space Sciences University of Texas at Dallas Richardson (UT Dallas) IPS Radio and Space Services 2002 https://hal.science/hal-00317180 https://hal.science/hal-00317180/document https://hal.science/hal-00317180/file/angeo-20-1617-2002.pdf en eng HAL CCSD European Geosciences Union hal-00317180 https://hal.science/hal-00317180 https://hal.science/hal-00317180/document https://hal.science/hal-00317180/file/angeo-20-1617-2002.pdf info:eu-repo/semantics/OpenAccess ISSN: 0992-7689 EISSN: 1432-0576 Annales Geophysicae https://hal.science/hal-00317180 Annales Geophysicae, 2002, 20 (10), pp.1617-1630 [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences info:eu-repo/semantics/article Journal articles 2002 ftinsu 2023-10-25T16:25:19Z International audience The geomagnetic conditions were moderately disturbed ( K p = 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 ... Article in Journal/Newspaper Macquarie Island Institut national des sciences de l'Univers: HAL-INSU |
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Open Polar |
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Institut national des sciences de l'Univers: HAL-INSU |
op_collection_id |
ftinsu |
language |
English |
topic |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
spellingShingle |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences 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 |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
description |
International audience The geomagnetic conditions were moderately disturbed ( K p = 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 ... |
author2 |
Department of Physics Victoria La Trobe University Melbourne British Antarctic Survey (BAS) Natural Environment Research Council (NERC) Department of Electronic Engineering Australia William B. Hanson Center for Space Sciences University of Texas at Dallas Richardson (UT Dallas) IPS Radio and Space Services |
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 |
HAL CCSD |
publishDate |
2002 |
url |
https://hal.science/hal-00317180 https://hal.science/hal-00317180/document https://hal.science/hal-00317180/file/angeo-20-1617-2002.pdf |
genre |
Macquarie Island |
genre_facet |
Macquarie Island |
op_source |
ISSN: 0992-7689 EISSN: 1432-0576 Annales Geophysicae https://hal.science/hal-00317180 Annales Geophysicae, 2002, 20 (10), pp.1617-1630 |
op_relation |
hal-00317180 https://hal.science/hal-00317180 https://hal.science/hal-00317180/document https://hal.science/hal-00317180/file/angeo-20-1617-2002.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1782336567235313664 |