Evolution of magnetic clouds in the inner heliosphere
Magnetic clouds (MCs) are objects in expansion during their travel through the heliosphere. In situ observations indicate that their front travel faster than their back, showing a clear empirical signature of expansion. With the aim of quantifying the expansion rate of MCs in the inner heliosphere (...
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2010
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| Acceso en línea: | http://hdl.handle.net/20.500.12110/paper_0094243X_v1216_n_p391_Gulisano https://repositoriouba.sisbi.uba.ar/gsdl/cgi-bin/library.cgi?a=d&c=artiaex&d=paper_0094243X_v1216_n_p391_Gulisano_oai |
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I28-R145-paper_0094243X_v1216_n_p391_Gulisano_oai2024-08-16 Gulisano, A.M. Démoulin, P. Dasso, S. Ruiz, M.E. Marsch, E. 2010 Magnetic clouds (MCs) are objects in expansion during their travel through the heliosphere. In situ observations indicate that their front travel faster than their back, showing a clear empirical signature of expansion. With the aim of quantifying the expansion rate of MCs in the inner heliosphere (0.3 to 1 AU), we present here a statistical study of events observed by the spacecraft Helios 1 and 2, during their complete period of operations. From the analysis of the profile of the MC magnetic field components in its local frame, which is obtained from a rotation of the observed magnetic field vectors to a system of reference oriented as the main axis of the flux rope, we revise a list of events identified in previous works and redefine improved MC boundaries/orientation for each event. We then split the sample into two subsets according to the characteristics of their velocity profiles, (a) those MCs with a significantly perturbed velocity profile due to the interaction with their surrounding solar wind (i.e. overtaken by streams) and (b) those that are not perturbed. We compute the dimensionless local expansion rate (ζ) for MCs defined by several works [e.g. Démoulin et al., Solar Phys, 250, 347-374 (2008)]. We find significantly different distribution of values for ζ when perturbed and non perturbed events are considered. Non perturbed MCs expand at rates ζ consistent with the expected value from the global pressure decay in the surrounding solar wind for increasing helio-distances, while perturbed ones may present strong departures from that global rule. We interpret these departures of ζ for perturbed MCs as a consequence of interaction with streams on their expansion. © 2010 American Institute of Physics. 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_0094243X_v1216_n_p391_Gulisano info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar AIP Conf. Proc. 2010;1216:391-394 Interplanetary physics Magnetic clouds Solar Wind Evolution of magnetic clouds in the inner heliosphere info:eu-repo/semantics/conferenceObject info:ar-repo/semantics/documento de conferencia info:eu-repo/semantics/publishedVersion https://repositoriouba.sisbi.uba.ar/gsdl/cgi-bin/library.cgi?a=d&c=artiaex&d=paper_0094243X_v1216_n_p391_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 |
Interplanetary physics Magnetic clouds Solar Wind |
| spellingShingle |
Interplanetary physics Magnetic clouds Solar Wind Gulisano, A.M. Démoulin, P. Dasso, S. Ruiz, M.E. Marsch, E. Evolution of magnetic clouds in the inner heliosphere |
| topic_facet |
Interplanetary physics Magnetic clouds Solar Wind |
| description |
Magnetic clouds (MCs) are objects in expansion during their travel through the heliosphere. In situ observations indicate that their front travel faster than their back, showing a clear empirical signature of expansion. With the aim of quantifying the expansion rate of MCs in the inner heliosphere (0.3 to 1 AU), we present here a statistical study of events observed by the spacecraft Helios 1 and 2, during their complete period of operations. From the analysis of the profile of the MC magnetic field components in its local frame, which is obtained from a rotation of the observed magnetic field vectors to a system of reference oriented as the main axis of the flux rope, we revise a list of events identified in previous works and redefine improved MC boundaries/orientation for each event. We then split the sample into two subsets according to the characteristics of their velocity profiles, (a) those MCs with a significantly perturbed velocity profile due to the interaction with their surrounding solar wind (i.e. overtaken by streams) and (b) those that are not perturbed. We compute the dimensionless local expansion rate (ζ) for MCs defined by several works [e.g. Démoulin et al., Solar Phys, 250, 347-374 (2008)]. We find significantly different distribution of values for ζ when perturbed and non perturbed events are considered. Non perturbed MCs expand at rates ζ consistent with the expected value from the global pressure decay in the surrounding solar wind for increasing helio-distances, while perturbed ones may present strong departures from that global rule. We interpret these departures of ζ for perturbed MCs as a consequence of interaction with streams on their expansion. © 2010 American Institute of Physics. |
| format |
Documento de conferencia Documento de conferencia 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 |
Evolution of magnetic clouds in the inner heliosphere |
| title_short |
Evolution of magnetic clouds in the inner heliosphere |
| title_full |
Evolution of magnetic clouds in the inner heliosphere |
| title_fullStr |
Evolution of magnetic clouds in the inner heliosphere |
| title_full_unstemmed |
Evolution of magnetic clouds in the inner heliosphere |
| title_sort |
evolution of magnetic clouds in the inner heliosphere |
| publishDate |
2010 |
| url |
http://hdl.handle.net/20.500.12110/paper_0094243X_v1216_n_p391_Gulisano https://repositoriouba.sisbi.uba.ar/gsdl/cgi-bin/library.cgi?a=d&c=artiaex&d=paper_0094243X_v1216_n_p391_Gulisano_oai |
| work_keys_str_mv |
AT gulisanoam evolutionofmagneticcloudsintheinnerheliosphere AT demoulinp evolutionofmagneticcloudsintheinnerheliosphere AT dassos evolutionofmagneticcloudsintheinnerheliosphere AT ruizme evolutionofmagneticcloudsintheinnerheliosphere AT marsche evolutionofmagneticcloudsintheinnerheliosphere |
| _version_ |
1809356896486817792 |