Progressive transformation of a flux rope to an ICME : CCComparative analysis using the direct and fitted expansion methods

The solar wind conditions at one astronomical unit (AU) can be strongly disturbed by interplanetary coronal mass ejections (ICMEs). A subset, called magnetic clouds (MCs), is formed by twisted flux ropes that transport an important amount of magnetic flux and helicity, which is released in CMEs. At...

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Autores principales: Dasso, Sergio Ricardo, Nakwacki, Maria Soledad, Mandrini, Cristina Hemilse
Publicado: 2007
Materias:
Coronal mass ejection: interplanetary
Magnetic fields: interplanetary
Magnetic reconnection: observational signatures
Solar wind: disturbances
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00380938_v244_n1-2_p115_Dasso
http://hdl.handle.net/20.500.12110/paper_00380938_v244_n1-2_p115_Dasso
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id paper:paper_00380938_v244_n1-2_p115_Dasso
record_format dspace
spelling paper:paper_00380938_v244_n1-2_p115_Dasso2023-06-08T15:02:41Z Progressive transformation of a flux rope to an ICME : CCComparative analysis using the direct and fitted expansion methods Dasso, Sergio Ricardo Nakwacki, Maria Soledad Mandrini, Cristina Hemilse Coronal mass ejection: interplanetary Magnetic fields: interplanetary Magnetic reconnection: observational signatures Solar wind: disturbances The solar wind conditions at one astronomical unit (AU) can be strongly disturbed by interplanetary coronal mass ejections (ICMEs). A subset, called magnetic clouds (MCs), is formed by twisted flux ropes that transport an important amount of magnetic flux and helicity, which is released in CMEs. At 1 AU from the Sun, the magnetic structure of MCs is generally modeled by neglecting their expansion during the spacecraft crossing. However, in some cases, MCs present a significant expansion. We present here an analysis of the huge and significantly expanding MC observed by the Wind spacecraft during 9∈-∈10 November 2004. This MC was embedded in an ICME. After determining an approximate orientation for the flux rope using the minimum variance method, we obtain a precise orientation of the cloud axis by relating its front and rear magnetic discontinuities using a direct method. This method takes into account the conservation of the azimuthal magnetic flux between the inbound and outbound branches and is valid for a finite impact parameter (i.e., not necessarily a small distance between the spacecraft trajectory and the cloud axis). The MC is also studied using dynamic models with isotropic expansion. We have found (6.2±1.5)×1020 Mx for the axial flux and (78±18)×1020 Mx for the azimuthal flux. Moreover, using the direct method, we find that the ICME is formed by a flux rope (MC) followed by an extended coherent magnetic region. These observations are interpreted by considering the existence of a previously larger flux rope, which partially reconnected with its environment in the front. We estimate that the reconnection process started close to the Sun. These findings imply that the ejected flux rope is progressively peeled by reconnection and transformed to the observed ICME (with a remnant flux rope in the front part). © 2007 Springer Science+Business Media B.V. Fil:Dasso, S. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Nakwacki, M.S. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Mandrini, C.H. 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_p115_Dasso http://hdl.handle.net/20.500.12110/paper_00380938_v244_n1-2_p115_Dasso
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Coronal mass ejection: interplanetary
Magnetic fields: interplanetary
Magnetic reconnection: observational signatures
Solar wind: disturbances
spellingShingle Coronal mass ejection: interplanetary
Magnetic fields: interplanetary
Magnetic reconnection: observational signatures
Solar wind: disturbances
Dasso, Sergio Ricardo
Nakwacki, Maria Soledad
Mandrini, Cristina Hemilse
Progressive transformation of a flux rope to an ICME : CCComparative analysis using the direct and fitted expansion methods
topic_facet Coronal mass ejection: interplanetary
Magnetic fields: interplanetary
Magnetic reconnection: observational signatures
Solar wind: disturbances
description The solar wind conditions at one astronomical unit (AU) can be strongly disturbed by interplanetary coronal mass ejections (ICMEs). A subset, called magnetic clouds (MCs), is formed by twisted flux ropes that transport an important amount of magnetic flux and helicity, which is released in CMEs. At 1 AU from the Sun, the magnetic structure of MCs is generally modeled by neglecting their expansion during the spacecraft crossing. However, in some cases, MCs present a significant expansion. We present here an analysis of the huge and significantly expanding MC observed by the Wind spacecraft during 9∈-∈10 November 2004. This MC was embedded in an ICME. After determining an approximate orientation for the flux rope using the minimum variance method, we obtain a precise orientation of the cloud axis by relating its front and rear magnetic discontinuities using a direct method. This method takes into account the conservation of the azimuthal magnetic flux between the inbound and outbound branches and is valid for a finite impact parameter (i.e., not necessarily a small distance between the spacecraft trajectory and the cloud axis). The MC is also studied using dynamic models with isotropic expansion. We have found (6.2±1.5)×1020 Mx for the axial flux and (78±18)×1020 Mx for the azimuthal flux. Moreover, using the direct method, we find that the ICME is formed by a flux rope (MC) followed by an extended coherent magnetic region. These observations are interpreted by considering the existence of a previously larger flux rope, which partially reconnected with its environment in the front. We estimate that the reconnection process started close to the Sun. These findings imply that the ejected flux rope is progressively peeled by reconnection and transformed to the observed ICME (with a remnant flux rope in the front part). © 2007 Springer Science+Business Media B.V.
author Dasso, Sergio Ricardo
Nakwacki, Maria Soledad
Mandrini, Cristina Hemilse
author_facet Dasso, Sergio Ricardo
Nakwacki, Maria Soledad
Mandrini, Cristina Hemilse
author_sort Dasso, Sergio Ricardo
title Progressive transformation of a flux rope to an ICME : CCComparative analysis using the direct and fitted expansion methods
title_short Progressive transformation of a flux rope to an ICME : CCComparative analysis using the direct and fitted expansion methods
title_full Progressive transformation of a flux rope to an ICME : CCComparative analysis using the direct and fitted expansion methods
title_fullStr Progressive transformation of a flux rope to an ICME : CCComparative analysis using the direct and fitted expansion methods
title_full_unstemmed Progressive transformation of a flux rope to an ICME : CCComparative analysis using the direct and fitted expansion methods
title_sort progressive transformation of a flux rope to an icme : cccomparative analysis using the direct and fitted expansion methods
publishDate 2007
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00380938_v244_n1-2_p115_Dasso
http://hdl.handle.net/20.500.12110/paper_00380938_v244_n1-2_p115_Dasso
work_keys_str_mv AT dassosergioricardo progressivetransformationofafluxropetoanicmecccomparativeanalysisusingthedirectandfittedexpansionmethods
AT nakwackimariasoledad progressivetransformationofafluxropetoanicmecccomparativeanalysisusingthedirectandfittedexpansionmethods
AT mandrinicristinahemilse progressivetransformationofafluxropetoanicmecccomparativeanalysisusingthedirectandfittedexpansionmethods
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