Twist and writhe of δ-island active regions

We study the magnetic helicity properties of a set of peculiar active regions (ARs) including δ-islands and other high-tilt bipolar configurations. These ARs are usually identified as the most active in terms of flare and CME production. Due to their observed structure, they have been associated wit...

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Autores principales: López Fuentes, M.C., Mandrini, C.H., Démoulin, P., Choudhary D.P., Strassmeier K.G.
Formato: SER
Materias:
Sun: activity
Sun: corona
Sun: magnetic fields
Sun: photosphere
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_17439213_v6_nS273_p153_LopezFuentes
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id todo:paper_17439213_v6_nS273_p153_LopezFuentes
record_format dspace
spelling todo:paper_17439213_v6_nS273_p153_LopezFuentes2023-10-03T16:31:35Z Twist and writhe of δ-island active regions López Fuentes, M.C. Mandrini, C.H. Démoulin, P. Choudhary D.P. Strassmeier K.G. Sun: activity Sun: corona Sun: magnetic fields Sun: photosphere We study the magnetic helicity properties of a set of peculiar active regions (ARs) including δ-islands and other high-tilt bipolar configurations. These ARs are usually identified as the most active in terms of flare and CME production. Due to their observed structure, they have been associated with the emergence of magnetic flux tubes that develop a kink instability. Our main goal is to determine the chirality of the twist and writhe components of the AR magnetic helicity in order to set constrains on the possible mechanisms producing the flux tube deformations. We determine the magnetic twist comparing observations of the AR coronal structure with force-free models of the magnetic field. We infer the flux-tube writhe from the rotation of the main magnetic bipole during the observed evolution. From the relation between the obtained twist and writhe signs we conclude that the development of the kink instability cannot be the single mechanism producing deformed flux-tubes. © International Astronomical Union 2011. SER info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_17439213_v6_nS273_p153_LopezFuentes
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Sun: activity
Sun: corona
Sun: magnetic fields
Sun: photosphere
spellingShingle Sun: activity
Sun: corona
Sun: magnetic fields
Sun: photosphere
López Fuentes, M.C.
Mandrini, C.H.
Démoulin, P.
Choudhary D.P.
Strassmeier K.G.
Twist and writhe of δ-island active regions
topic_facet Sun: activity
Sun: corona
Sun: magnetic fields
Sun: photosphere
description We study the magnetic helicity properties of a set of peculiar active regions (ARs) including δ-islands and other high-tilt bipolar configurations. These ARs are usually identified as the most active in terms of flare and CME production. Due to their observed structure, they have been associated with the emergence of magnetic flux tubes that develop a kink instability. Our main goal is to determine the chirality of the twist and writhe components of the AR magnetic helicity in order to set constrains on the possible mechanisms producing the flux tube deformations. We determine the magnetic twist comparing observations of the AR coronal structure with force-free models of the magnetic field. We infer the flux-tube writhe from the rotation of the main magnetic bipole during the observed evolution. From the relation between the obtained twist and writhe signs we conclude that the development of the kink instability cannot be the single mechanism producing deformed flux-tubes. © International Astronomical Union 2011.
format SER
author López Fuentes, M.C.
Mandrini, C.H.
Démoulin, P.
Choudhary D.P.
Strassmeier K.G.
author_facet López Fuentes, M.C.
Mandrini, C.H.
Démoulin, P.
Choudhary D.P.
Strassmeier K.G.
author_sort López Fuentes, M.C.
title Twist and writhe of δ-island active regions
title_short Twist and writhe of δ-island active regions
title_full Twist and writhe of δ-island active regions
title_fullStr Twist and writhe of δ-island active regions
title_full_unstemmed Twist and writhe of δ-island active regions
title_sort twist and writhe of δ-island active regions
url http://hdl.handle.net/20.500.12110/paper_17439213_v6_nS273_p153_LopezFuentes
work_keys_str_mv AT lopezfuentesmc twistandwritheofdislandactiveregions
AT mandrinich twistandwritheofdislandactiveregions
AT demoulinp twistandwritheofdislandactiveregions
AT choudharydp twistandwritheofdislandactiveregions
AT strassmeierkg twistandwritheofdislandactiveregions
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