Global and local expansion of magnetic clouds in the inner heliosphere

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Context: Observations of magnetic clouds (MCs) are consistent with the presence of flux ropes detected in the solar wind (SW) a few days after their expulsion from the Sun as coronal mass ejections (CMEs). Aims: Both the in situ observations of plasma velocity profiles and the increase of their size...

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Autores principales:	Gulisano, A.M., Démoulin, P., Dasso, S., Ruiz, M.E., Marsch, E.
Formato:	Artículo publishedVersion
Publicado:	2010
Materias:	Coronal mass ejections (CMEs) - Solar wind - Interplanetary medium Magnetic fields - Magnetohydrodynamics (MHD) - Sun Astrophysics Boundary layer flow Clouds Interplanetary spacecraft Magnetic fields Magnetohydrodynamics Semiconductor counters Solar wind Sun Velocity Velocity measurement Coronal mass ejection Interplanetary medium Magnetohydrodynamics suns Expansion
Acceso en línea:	http://hdl.handle.net/20.500.12110/paper_00046361_v509_n1_p_Gulisano https://repositoriouba.sisbi.uba.ar/gsdl/cgi-bin/library.cgi?a=d&c=artiaex&d=paper_00046361_v509_n1_p_Gulisano_oai
Aporte de:	Repositorio Digital de la Universidad de Buenos Aires (UBA) de Universidad de Buenos Aires

id	I28-R145-paper_00046361_v509_n1_p_Gulisano_oai
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spelling	I28-R145-paper_00046361_v509_n1_p_Gulisano_oai2024-08-16 Gulisano, A.M. Démoulin, P. Dasso, S. Ruiz, M.E. Marsch, E. 2010 Context: Observations of magnetic clouds (MCs) are consistent with the presence of flux ropes detected in the solar wind (SW) a few days after their expulsion from the Sun as coronal mass ejections (CMEs). Aims: Both the in situ observations of plasma velocity profiles and the increase of their size with solar distance show that MCs are typically expanding structures. The aim of this work is to derive the expansion properties of MCs in the inner heliosphere from 0.3 to 1 AU. Methods: We analyze MCs observed by the two Helios spacecraft using in situ magnetic field and velocity measurements. We split the sample in two subsets: those MCs with a velocity profile that is significantly perturbed from the expected linear profile and those that are not. From the slope of the in situ measured bulk velocity along the Sun-Earth direction, we compute an expansion speed with respect to the cloud center for each of the analyzed MCs. Results: We analyze how the expansion speed depends on the MC size, the translation velocity, and the heliocentric distance, finding that allMCs in the subset of non-perturbed MCs expand with almost the same non-dimensional expansion rate (ζ).We find departures from this general rule for ζ only for perturbed MCs, and we interpret the departures as the consequence of a local and strong SW perturbation by SW fast streams, affecting the MC even inside its interior, in addition to the direct interaction region between the SW and the MC. We also compute the dependence of the mean total SW pressure on the solar distance and we confirm that the decrease of the total SW pressure with distance is the main origin of the observed MC expansion rate. We found that ζ was 0.91 ± 0.23 for non-perturbed MCs while ζ was 0.48 ± 0.79 for perturbed MCs, the larger spread in the last ones being due to the influence of the solar wind local environment conditions on the expansion. © ESO 2010. Fil:Gulisano, A.M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Dasso, S. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Ruiz, M.E. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. application/pdf http://hdl.handle.net/20.500.12110/paper_00046361_v509_n1_p_Gulisano info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar Astron. Astrophys. 2010;509(1) Coronal mass ejections (CMEs) - Solar wind - Interplanetary medium Magnetic fields - Magnetohydrodynamics (MHD) - Sun Astrophysics Boundary layer flow Clouds Interplanetary spacecraft Magnetic fields Magnetohydrodynamics Semiconductor counters Solar wind Sun Velocity Velocity measurement Coronal mass ejection Coronal mass ejections (CMEs) - Solar wind - Interplanetary medium Interplanetary medium Magnetohydrodynamics suns Expansion Global and local expansion of magnetic clouds in the inner heliosphere info:eu-repo/semantics/article info:ar-repo/semantics/artículo info:eu-repo/semantics/publishedVersion https://repositoriouba.sisbi.uba.ar/gsdl/cgi-bin/library.cgi?a=d&c=artiaex&d=paper_00046361_v509_n1_p_Gulisano_oai
institution	Universidad de Buenos Aires
institution_str	I-28
repository_str	R-145
collection	Repositorio Digital de la Universidad de Buenos Aires (UBA)
topic	Coronal mass ejections (CMEs) - Solar wind - Interplanetary medium Magnetic fields - Magnetohydrodynamics (MHD) - Sun Astrophysics Boundary layer flow Clouds Interplanetary spacecraft Magnetic fields Magnetohydrodynamics Semiconductor counters Solar wind Sun Velocity Velocity measurement Coronal mass ejection Coronal mass ejections (CMEs) - Solar wind - Interplanetary medium Interplanetary medium Magnetohydrodynamics suns Expansion
spellingShingle	Coronal mass ejections (CMEs) - Solar wind - Interplanetary medium Magnetic fields - Magnetohydrodynamics (MHD) - Sun Astrophysics Boundary layer flow Clouds Interplanetary spacecraft Magnetic fields Magnetohydrodynamics Semiconductor counters Solar wind Sun Velocity Velocity measurement Coronal mass ejection Coronal mass ejections (CMEs) - Solar wind - Interplanetary medium Interplanetary medium Magnetohydrodynamics suns Expansion Gulisano, A.M. Démoulin, P. Dasso, S. Ruiz, M.E. Marsch, E. Global and local expansion of magnetic clouds in the inner heliosphere
topic_facet	Coronal mass ejections (CMEs) - Solar wind - Interplanetary medium Magnetic fields - Magnetohydrodynamics (MHD) - Sun Astrophysics Boundary layer flow Clouds Interplanetary spacecraft Magnetic fields Magnetohydrodynamics Semiconductor counters Solar wind Sun Velocity Velocity measurement Coronal mass ejection Coronal mass ejections (CMEs) - Solar wind - Interplanetary medium Interplanetary medium Magnetohydrodynamics suns Expansion
description	Context: Observations of magnetic clouds (MCs) are consistent with the presence of flux ropes detected in the solar wind (SW) a few days after their expulsion from the Sun as coronal mass ejections (CMEs). Aims: Both the in situ observations of plasma velocity profiles and the increase of their size with solar distance show that MCs are typically expanding structures. The aim of this work is to derive the expansion properties of MCs in the inner heliosphere from 0.3 to 1 AU. Methods: We analyze MCs observed by the two Helios spacecraft using in situ magnetic field and velocity measurements. We split the sample in two subsets: those MCs with a velocity profile that is significantly perturbed from the expected linear profile and those that are not. From the slope of the in situ measured bulk velocity along the Sun-Earth direction, we compute an expansion speed with respect to the cloud center for each of the analyzed MCs. Results: We analyze how the expansion speed depends on the MC size, the translation velocity, and the heliocentric distance, finding that allMCs in the subset of non-perturbed MCs expand with almost the same non-dimensional expansion rate (ζ).We find departures from this general rule for ζ only for perturbed MCs, and we interpret the departures as the consequence of a local and strong SW perturbation by SW fast streams, affecting the MC even inside its interior, in addition to the direct interaction region between the SW and the MC. We also compute the dependence of the mean total SW pressure on the solar distance and we confirm that the decrease of the total SW pressure with distance is the main origin of the observed MC expansion rate. We found that ζ was 0.91 ± 0.23 for non-perturbed MCs while ζ was 0.48 ± 0.79 for perturbed MCs, the larger spread in the last ones being due to the influence of the solar wind local environment conditions on the expansion. © ESO 2010.
format	Artículo Artículo publishedVersion
author	Gulisano, A.M. Démoulin, P. Dasso, S. Ruiz, M.E. Marsch, E.
author_facet	Gulisano, A.M. Démoulin, P. Dasso, S. Ruiz, M.E. Marsch, E.
author_sort	Gulisano, A.M.
title	Global and local expansion of magnetic clouds in the inner heliosphere
title_short	Global and local expansion of magnetic clouds in the inner heliosphere
title_full	Global and local expansion of magnetic clouds in the inner heliosphere
title_fullStr	Global and local expansion of magnetic clouds in the inner heliosphere
title_full_unstemmed	Global and local expansion of magnetic clouds in the inner heliosphere
title_sort	global and local expansion of magnetic clouds in the inner heliosphere
publishDate	2010
url	http://hdl.handle.net/20.500.12110/paper_00046361_v509_n1_p_Gulisano https://repositoriouba.sisbi.uba.ar/gsdl/cgi-bin/library.cgi?a=d&c=artiaex&d=paper_00046361_v509_n1_p_Gulisano_oai
work_keys_str_mv	AT gulisanoam globalandlocalexpansionofmagneticcloudsintheinnerheliosphere AT demoulinp globalandlocalexpansionofmagneticcloudsintheinnerheliosphere AT dassos globalandlocalexpansionofmagneticcloudsintheinnerheliosphere AT ruizme globalandlocalexpansionofmagneticcloudsintheinnerheliosphere AT marsche globalandlocalexpansionofmagneticcloudsintheinnerheliosphere
_version_	1809357048053235712

Global and local expansion of magnetic clouds in the inner heliosphere

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