Characteristics of merging at the magnetopause inferred from dayside 557.7-nm all-sky images: IMF drivers of poleward moving auroral forms
International audience We combine in situ measurements from Cluster with high-resolution 557.7 nm all-sky images from South Pole to investigate the spatial and temporal evolution of merging on the dayside magnetopause. Variations of 557.7 nm emissions were observed at a 6 s cadence at South Pole on...
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Format: | Article in Journal/Newspaper |
Language: | English |
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HAL CCSD
2006
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Online Access: | https://hal.science/hal-00330097 https://hal.science/hal-00330097/document https://hal.science/hal-00330097/file/angeo-24-3071-2006.pdf |
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ftutoulouse3hal:oai:HAL:hal-00330097v1 |
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openpolar |
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Open Polar |
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Université Toulouse III - Paul Sabatier: HAL-UPS |
op_collection_id |
ftutoulouse3hal |
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 Maynard, N. C. Burke, W. J. Ebihara, Y. Ober, D. M. Wilson, G. R. Siebert, K. D. Winningham, J. D. Lanzerotti, L. J. Farrugia, C. J. Ejiri, M. Rème, H. Balogh, A. Fazakerley, A. Characteristics of merging at the magnetopause inferred from dayside 557.7-nm all-sky images: IMF drivers of poleward moving auroral forms |
topic_facet |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
description |
International audience We combine in situ measurements from Cluster with high-resolution 557.7 nm all-sky images from South Pole to investigate the spatial and temporal evolution of merging on the dayside magnetopause. Variations of 557.7 nm emissions were observed at a 6 s cadence at South Pole on 29 April 2003 while significant changes in the Interplanetary Magnetic Field (IMF) clock angle were reaching the magnetopause. Electrons energized at merging sites are the probable sources for 557.7 nm cusp emissions. At the same time Cluster was crossing the pre-noon cusp in the Northern Hemisphere. The combined observations confirm results of a previous study that merging events can occur at multiple sites simultaneously and vary asynchronously on time scales of 10 s to 3 min (Maynard et al., 2004). The intensity of the emissions and the merging rate appear to vary with changes in the IMF clock angle, IMF B X and the dynamic pressure of the solar wind. Most poleward moving auroral forms (PMAFs) reflect responses to changes in interplanetary medium rather than to local processes. The changes in magnetopause position required by increases in dynamic pressure are mediated by merging and result in the generation of PMAFs. Small (15–20%) variations in dynamic pressure of the solar wind are sufficient to launch PMAFs. Changes in IMF B X create magnetic flux compressions and rarefactions in the solar wind. Increases (decreases) in IMF B X strengthens | B | near northern (southern) hemisphere merging sites thereby enhancing merging rates and triggering PMAFs. When correlating responses in the two hemispheres, the presence of significant IMF B X also requires that different lag-times be applied to ACE measurements acquired ~0.1 AU upstream of Earth. Cluster observations set lag times for merging at Northern Hemisphere sites; post-noon optical emissions set times of Southern Hemisphere merging. All-sky images and magnetohydrodynamic simulations indicate that merging occurs in multiple discrete locations, rather than ... |
author2 |
EOS Space Science Center Durham University of New Hampshire (UNH) Air Force Research Laboratory (AFRL) United States Air Force (USAF) National Institute of Polar Research Tokyo (NiPR) ATK Mission Research Department of Space Studies Boulder Southwest Research Institute Boulder (SwRI) New Jersey Institute of Technology Newark (NJIT) Centre d'étude spatiale des rayonnements (CESR) Université Toulouse III - Paul Sabatier (UT3) Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP) Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3) Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Centre National de la Recherche Scientifique (CNRS) Imperial College London Mullard Space Science Laboratory (MSSL) University College of London London (UCL) |
format |
Article in Journal/Newspaper |
author |
Maynard, N. C. Burke, W. J. Ebihara, Y. Ober, D. M. Wilson, G. R. Siebert, K. D. Winningham, J. D. Lanzerotti, L. J. Farrugia, C. J. Ejiri, M. Rème, H. Balogh, A. Fazakerley, A. |
author_facet |
Maynard, N. C. Burke, W. J. Ebihara, Y. Ober, D. M. Wilson, G. R. Siebert, K. D. Winningham, J. D. Lanzerotti, L. J. Farrugia, C. J. Ejiri, M. Rème, H. Balogh, A. Fazakerley, A. |
author_sort |
Maynard, N. C. |
title |
Characteristics of merging at the magnetopause inferred from dayside 557.7-nm all-sky images: IMF drivers of poleward moving auroral forms |
title_short |
Characteristics of merging at the magnetopause inferred from dayside 557.7-nm all-sky images: IMF drivers of poleward moving auroral forms |
title_full |
Characteristics of merging at the magnetopause inferred from dayside 557.7-nm all-sky images: IMF drivers of poleward moving auroral forms |
title_fullStr |
Characteristics of merging at the magnetopause inferred from dayside 557.7-nm all-sky images: IMF drivers of poleward moving auroral forms |
title_full_unstemmed |
Characteristics of merging at the magnetopause inferred from dayside 557.7-nm all-sky images: IMF drivers of poleward moving auroral forms |
title_sort |
characteristics of merging at the magnetopause inferred from dayside 557.7-nm all-sky images: imf drivers of poleward moving auroral forms |
publisher |
HAL CCSD |
publishDate |
2006 |
url |
https://hal.science/hal-00330097 https://hal.science/hal-00330097/document https://hal.science/hal-00330097/file/angeo-24-3071-2006.pdf |
genre |
South pole |
genre_facet |
South pole |
op_source |
ISSN: 0992-7689 EISSN: 1432-0576 Annales Geophysicae https://hal.science/hal-00330097 Annales Geophysicae, 2006, 24 (11), pp.3071-3098 |
op_relation |
hal-00330097 https://hal.science/hal-00330097 https://hal.science/hal-00330097/document https://hal.science/hal-00330097/file/angeo-24-3071-2006.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1810480460664406016 |
spelling |
ftutoulouse3hal:oai:HAL:hal-00330097v1 2024-09-15T18:36:45+00:00 Characteristics of merging at the magnetopause inferred from dayside 557.7-nm all-sky images: IMF drivers of poleward moving auroral forms Maynard, N. C. Burke, W. J. Ebihara, Y. Ober, D. M. Wilson, G. R. Siebert, K. D. Winningham, J. D. Lanzerotti, L. J. Farrugia, C. J. Ejiri, M. Rème, H. Balogh, A. Fazakerley, A. EOS Space Science Center Durham University of New Hampshire (UNH) Air Force Research Laboratory (AFRL) United States Air Force (USAF) National Institute of Polar Research Tokyo (NiPR) ATK Mission Research Department of Space Studies Boulder Southwest Research Institute Boulder (SwRI) New Jersey Institute of Technology Newark (NJIT) Centre d'étude spatiale des rayonnements (CESR) Université Toulouse III - Paul Sabatier (UT3) Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP) Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3) Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Centre National de la Recherche Scientifique (CNRS) Imperial College London Mullard Space Science Laboratory (MSSL) University College of London London (UCL) 2006-11-22 https://hal.science/hal-00330097 https://hal.science/hal-00330097/document https://hal.science/hal-00330097/file/angeo-24-3071-2006.pdf en eng HAL CCSD European Geosciences Union hal-00330097 https://hal.science/hal-00330097 https://hal.science/hal-00330097/document https://hal.science/hal-00330097/file/angeo-24-3071-2006.pdf info:eu-repo/semantics/OpenAccess ISSN: 0992-7689 EISSN: 1432-0576 Annales Geophysicae https://hal.science/hal-00330097 Annales Geophysicae, 2006, 24 (11), pp.3071-3098 [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 2006 ftutoulouse3hal 2024-06-25T00:12:06Z International audience We combine in situ measurements from Cluster with high-resolution 557.7 nm all-sky images from South Pole to investigate the spatial and temporal evolution of merging on the dayside magnetopause. Variations of 557.7 nm emissions were observed at a 6 s cadence at South Pole on 29 April 2003 while significant changes in the Interplanetary Magnetic Field (IMF) clock angle were reaching the magnetopause. Electrons energized at merging sites are the probable sources for 557.7 nm cusp emissions. At the same time Cluster was crossing the pre-noon cusp in the Northern Hemisphere. The combined observations confirm results of a previous study that merging events can occur at multiple sites simultaneously and vary asynchronously on time scales of 10 s to 3 min (Maynard et al., 2004). The intensity of the emissions and the merging rate appear to vary with changes in the IMF clock angle, IMF B X and the dynamic pressure of the solar wind. Most poleward moving auroral forms (PMAFs) reflect responses to changes in interplanetary medium rather than to local processes. The changes in magnetopause position required by increases in dynamic pressure are mediated by merging and result in the generation of PMAFs. Small (15–20%) variations in dynamic pressure of the solar wind are sufficient to launch PMAFs. Changes in IMF B X create magnetic flux compressions and rarefactions in the solar wind. Increases (decreases) in IMF B X strengthens | B | near northern (southern) hemisphere merging sites thereby enhancing merging rates and triggering PMAFs. When correlating responses in the two hemispheres, the presence of significant IMF B X also requires that different lag-times be applied to ACE measurements acquired ~0.1 AU upstream of Earth. Cluster observations set lag times for merging at Northern Hemisphere sites; post-noon optical emissions set times of Southern Hemisphere merging. All-sky images and magnetohydrodynamic simulations indicate that merging occurs in multiple discrete locations, rather than ... Article in Journal/Newspaper South pole Université Toulouse III - Paul Sabatier: HAL-UPS |