Properties of Magnetic Tongues over a Solar Cycle

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The photospheric spatial distribution of the main magnetic polarities of bipolar active regions (ARs) present during their emergence deformations are known as magnetic tongues. They are attributed to the presence of twist in the toroidal magnetic-flux tubes that form the ARs. The aim of this article...

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Autores principales:	Poisson, M., Démoulin, P., López Fuentes, M., Mandrini, C.H.
Formato:	JOUR
Materias:	Active regions, magnetic fields Corona, structures Helicity, magnetic Helicity, observations
Acceso en línea:	http://hdl.handle.net/20.500.12110/paper_00380938_v291_n6_p1625_Poisson
Aporte de:	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires

id	todo:paper_00380938_v291_n6_p1625_Poisson
record_format	dspace
spelling	todo:paper_00380938_v291_n6_p1625_Poisson2023-10-03T14:48:54Z Properties of Magnetic Tongues over a Solar Cycle Poisson, M. Démoulin, P. López Fuentes, M. Mandrini, C.H. Active regions, magnetic fields Corona, structures Helicity, magnetic Helicity, observations The photospheric spatial distribution of the main magnetic polarities of bipolar active regions (ARs) present during their emergence deformations are known as magnetic tongues. They are attributed to the presence of twist in the toroidal magnetic-flux tubes that form the ARs. The aim of this article is to study the twist of newly emerged ARs from the evolution of magnetic tongues observed in photospheric line-of-sight magnetograms. We apply the procedure described by Poisson et al. (Solar Phys.290, 727, 2015a) to ARs observed over the full Solar Cycle 23 and the beginning of Cycle 24. Our results show that the hemispherical rule obtained using the tongues as a proxy of the twist has a weak sign dominance (53 % in the southern hemisphere and 58 % in the northern hemisphere). By defining the variation of the tongue angle, we characterize the strength of the magnetic tongues during different phases of the AR emergence. We find that there is a tendency of the tongues to be stronger during the beginning of the emergence and to become weaker as the AR reaches its maximum magnetic flux. We compare this evolution with the emergence of a toroidal flux-rope model with non-uniform twist. The variety of evolution of the tongues in the analyzed ARs can only be reproduced when using a broad range of twist profiles, in particular having a large variety of twist gradients in the direction vertical to the photosphere. Although the analytical model used is a special case, selected to minimize the complexity of the problem, the results obtained set new observational constraints to theoretical models of flux-rope emergence that form bipolar ARs. © 2016, Springer Science+Business Media Dordrecht. Fil:Poisson, M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:López Fuentes, M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_00380938_v291_n6_p1625_Poisson
institution	Universidad de Buenos Aires
institution_str	I-28
repository_str	R-134
collection	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic	Active regions, magnetic fields Corona, structures Helicity, magnetic Helicity, observations
spellingShingle	Active regions, magnetic fields Corona, structures Helicity, magnetic Helicity, observations Poisson, M. Démoulin, P. López Fuentes, M. Mandrini, C.H. Properties of Magnetic Tongues over a Solar Cycle
topic_facet	Active regions, magnetic fields Corona, structures Helicity, magnetic Helicity, observations
description	The photospheric spatial distribution of the main magnetic polarities of bipolar active regions (ARs) present during their emergence deformations are known as magnetic tongues. They are attributed to the presence of twist in the toroidal magnetic-flux tubes that form the ARs. The aim of this article is to study the twist of newly emerged ARs from the evolution of magnetic tongues observed in photospheric line-of-sight magnetograms. We apply the procedure described by Poisson et al. (Solar Phys.290, 727, 2015a) to ARs observed over the full Solar Cycle 23 and the beginning of Cycle 24. Our results show that the hemispherical rule obtained using the tongues as a proxy of the twist has a weak sign dominance (53 % in the southern hemisphere and 58 % in the northern hemisphere). By defining the variation of the tongue angle, we characterize the strength of the magnetic tongues during different phases of the AR emergence. We find that there is a tendency of the tongues to be stronger during the beginning of the emergence and to become weaker as the AR reaches its maximum magnetic flux. We compare this evolution with the emergence of a toroidal flux-rope model with non-uniform twist. The variety of evolution of the tongues in the analyzed ARs can only be reproduced when using a broad range of twist profiles, in particular having a large variety of twist gradients in the direction vertical to the photosphere. Although the analytical model used is a special case, selected to minimize the complexity of the problem, the results obtained set new observational constraints to theoretical models of flux-rope emergence that form bipolar ARs. © 2016, Springer Science+Business Media Dordrecht.
format	JOUR
author	Poisson, M. Démoulin, P. López Fuentes, M. Mandrini, C.H.
author_facet	Poisson, M. Démoulin, P. López Fuentes, M. Mandrini, C.H.
author_sort	Poisson, M.
title	Properties of Magnetic Tongues over a Solar Cycle
title_short	Properties of Magnetic Tongues over a Solar Cycle
title_full	Properties of Magnetic Tongues over a Solar Cycle
title_fullStr	Properties of Magnetic Tongues over a Solar Cycle
title_full_unstemmed	Properties of Magnetic Tongues over a Solar Cycle
title_sort	properties of magnetic tongues over a solar cycle
url	http://hdl.handle.net/20.500.12110/paper_00380938_v291_n6_p1625_Poisson
work_keys_str_mv	AT poissonm propertiesofmagnetictonguesoverasolarcycle AT demoulinp propertiesofmagnetictonguesoverasolarcycle AT lopezfuentesm propertiesofmagnetictonguesoverasolarcycle AT mandrinich propertiesofmagnetictonguesoverasolarcycle
_version_	1807322578352603136

Properties of Magnetic Tongues over a Solar Cycle

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