Multi-spacecraft study of the 21 January 2005 ICME : EEEvidence of current sheet substructure near the periphery of a strongly expanding, fast magnetic cloud

We examine the near-Earth Interplanetary Coronal Mass Ejection (ICME) apparently related to the intense Solar Energetic Particle (SEP) event of 20 January 2005. Our purpose is to contribute to the understanding of the macroscopic structure, evolution and dynamics of the solar corona and heliosphere....

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Autor principal: Dasso, Sergio Ricardo
Publicado: 2007
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00380938_v244_n1-2_p139_Foullon
http://hdl.handle.net/20.500.12110/paper_00380938_v244_n1-2_p139_Foullon
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
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spelling paper:paper_00380938_v244_n1-2_p139_Foullon2023-06-08T15:02:41Z Multi-spacecraft study of the 21 January 2005 ICME : EEEvidence of current sheet substructure near the periphery of a strongly expanding, fast magnetic cloud Dasso, Sergio Ricardo We examine the near-Earth Interplanetary Coronal Mass Ejection (ICME) apparently related to the intense Solar Energetic Particle (SEP) event of 20 January 2005. Our purpose is to contribute to the understanding of the macroscopic structure, evolution and dynamics of the solar corona and heliosphere. Using Cluster, ACE and Wind data in the solar wind, and Geotail data in the magnetosheath, we perform a multi-spacecraft analysis of the ICME-driven shock, post-shock magnetic discontinuities and ejecta. Traversals by the well-separated near-Earth spacecraft provide a coherent picture of the ICME geometry. Following the shock, the ICME sequence starts with a hot pileup, i.e.,∈ a sheath, followed by a fast ejecta characterised by a non-compressive density enhancement (NCDE), which is caused essentially by an enrichment in helium. The plasma and magnetic observations of the ejecta are consistent with the outskirts of a structure in strong expansion, consisting of nested magnetic loops still connected to the Sun. Within the leading edge of the ejecta, we establish the presence of a tilted current sheet substructure. An analysis of the observations suggests that the tilted current sheet is draped within the overlying cloud canopy, ahead of a magnetic cloud-like structure. The flux rope interpretation of this structure near L1, confirmed by observations of the corresponding magnetic cloud, provided by Ulysses at 5.3 AU and away from the Sun∈-∈Earth line, indicates that the bulk of the cloud is in the northwest sector as seen from the Earth, with its axis nearly perpendicular to the ecliptic. This is consistent with the primary direction of travel of the fast halo CME observed at the Sun. Moreover, the NCDE and helium enrichment are consistent with the position near the streamer belt of the flaring active region NOAA 10720 associated with the CME. However, differences between interplanetary and solar observations indicate a large rotation of the erupting filament and overlying arcade, which can be attributed to the flux rope being subject to the helical kink instability. © 2007 Springer. Fil:Dasso, S. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2007 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00380938_v244_n1-2_p139_Foullon http://hdl.handle.net/20.500.12110/paper_00380938_v244_n1-2_p139_Foullon
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
description We examine the near-Earth Interplanetary Coronal Mass Ejection (ICME) apparently related to the intense Solar Energetic Particle (SEP) event of 20 January 2005. Our purpose is to contribute to the understanding of the macroscopic structure, evolution and dynamics of the solar corona and heliosphere. Using Cluster, ACE and Wind data in the solar wind, and Geotail data in the magnetosheath, we perform a multi-spacecraft analysis of the ICME-driven shock, post-shock magnetic discontinuities and ejecta. Traversals by the well-separated near-Earth spacecraft provide a coherent picture of the ICME geometry. Following the shock, the ICME sequence starts with a hot pileup, i.e.,∈ a sheath, followed by a fast ejecta characterised by a non-compressive density enhancement (NCDE), which is caused essentially by an enrichment in helium. The plasma and magnetic observations of the ejecta are consistent with the outskirts of a structure in strong expansion, consisting of nested magnetic loops still connected to the Sun. Within the leading edge of the ejecta, we establish the presence of a tilted current sheet substructure. An analysis of the observations suggests that the tilted current sheet is draped within the overlying cloud canopy, ahead of a magnetic cloud-like structure. The flux rope interpretation of this structure near L1, confirmed by observations of the corresponding magnetic cloud, provided by Ulysses at 5.3 AU and away from the Sun∈-∈Earth line, indicates that the bulk of the cloud is in the northwest sector as seen from the Earth, with its axis nearly perpendicular to the ecliptic. This is consistent with the primary direction of travel of the fast halo CME observed at the Sun. Moreover, the NCDE and helium enrichment are consistent with the position near the streamer belt of the flaring active region NOAA 10720 associated with the CME. However, differences between interplanetary and solar observations indicate a large rotation of the erupting filament and overlying arcade, which can be attributed to the flux rope being subject to the helical kink instability. © 2007 Springer.
author Dasso, Sergio Ricardo
spellingShingle Dasso, Sergio Ricardo
Multi-spacecraft study of the 21 January 2005 ICME : EEEvidence of current sheet substructure near the periphery of a strongly expanding, fast magnetic cloud
author_facet Dasso, Sergio Ricardo
author_sort Dasso, Sergio Ricardo
title Multi-spacecraft study of the 21 January 2005 ICME : EEEvidence of current sheet substructure near the periphery of a strongly expanding, fast magnetic cloud
title_short Multi-spacecraft study of the 21 January 2005 ICME : EEEvidence of current sheet substructure near the periphery of a strongly expanding, fast magnetic cloud
title_full Multi-spacecraft study of the 21 January 2005 ICME : EEEvidence of current sheet substructure near the periphery of a strongly expanding, fast magnetic cloud
title_fullStr Multi-spacecraft study of the 21 January 2005 ICME : EEEvidence of current sheet substructure near the periphery of a strongly expanding, fast magnetic cloud
title_full_unstemmed Multi-spacecraft study of the 21 January 2005 ICME : EEEvidence of current sheet substructure near the periphery of a strongly expanding, fast magnetic cloud
title_sort multi-spacecraft study of the 21 january 2005 icme : eeevidence of current sheet substructure near the periphery of a strongly expanding, fast magnetic cloud
publishDate 2007
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00380938_v244_n1-2_p139_Foullon
http://hdl.handle.net/20.500.12110/paper_00380938_v244_n1-2_p139_Foullon
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