Distribution of electric currents in sunspots from photosphere to corona

We present a study of two regular sunspots that exhibit nearly uniform twist from the photosphere to the corona. We derive the twist parameter in the corona and in the chromosphere by minimizing the difference between the extrapolated linear force-free field model field lines and the observed intens...

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Autores principales: Gosain, S., Démoulin, P., López Fuentes, M.
Formato: JOUR
Materias:
magnetic fields
Sun: chromosphere
Sun: corona
Sun: photosphere
sunspots
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_0004637X_v793_n1_p_Gosain
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
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spelling todo:paper_0004637X_v793_n1_p_Gosain2023-10-03T14:02:35Z Distribution of electric currents in sunspots from photosphere to corona Gosain, S. Démoulin, P. López Fuentes, M. magnetic fields Sun: chromosphere Sun: corona Sun: photosphere sunspots We present a study of two regular sunspots that exhibit nearly uniform twist from the photosphere to the corona. We derive the twist parameter in the corona and in the chromosphere by minimizing the difference between the extrapolated linear force-free field model field lines and the observed intensity structures in the extreme-ultraviolet images of the Sun. The chromospheric structures appear more twisted than the coronal structures by a factor of two. Further, we derive the vertical component of electric current density, jz, using vector magnetograms from the Hinode Solar Optical Telescope (SOT). The spatial distribution of jzhas a zebra pattern of strong positive and negative values owing to the penumbral fibril structure resolved by Hinode/SOT. This zebra pattern is due to the derivative of the horizontal magnetic field across the thin fibrils; therefore, it is strong and masks weaker currents that might be present, for example, as a result of the twist of the sunspot. We decompose jzinto the contribution due to the derivatives along and across the direction of the horizontal field, which follows the fibril orientation closely. The map of the tangential component has more distributed currents that are coherent with the chromospheric and coronal twisted structures. Moreover, it allows us to map and identify the direct and return currents in the sunspots. Finally, this decomposition of jzis general and can be applied to any vector magnetogram in order to better identify the weaker large-scale currents that are associated with coronal twisted/sheared structures. © 2014. The American Astronomical Society. All rights reserved.. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_0004637X_v793_n1_p_Gosain
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic magnetic fields
Sun: chromosphere
Sun: corona
Sun: photosphere
sunspots
spellingShingle magnetic fields
Sun: chromosphere
Sun: corona
Sun: photosphere
sunspots
Gosain, S.
Démoulin, P.
López Fuentes, M.
Distribution of electric currents in sunspots from photosphere to corona
topic_facet magnetic fields
Sun: chromosphere
Sun: corona
Sun: photosphere
sunspots
description We present a study of two regular sunspots that exhibit nearly uniform twist from the photosphere to the corona. We derive the twist parameter in the corona and in the chromosphere by minimizing the difference between the extrapolated linear force-free field model field lines and the observed intensity structures in the extreme-ultraviolet images of the Sun. The chromospheric structures appear more twisted than the coronal structures by a factor of two. Further, we derive the vertical component of electric current density, jz, using vector magnetograms from the Hinode Solar Optical Telescope (SOT). The spatial distribution of jzhas a zebra pattern of strong positive and negative values owing to the penumbral fibril structure resolved by Hinode/SOT. This zebra pattern is due to the derivative of the horizontal magnetic field across the thin fibrils; therefore, it is strong and masks weaker currents that might be present, for example, as a result of the twist of the sunspot. We decompose jzinto the contribution due to the derivatives along and across the direction of the horizontal field, which follows the fibril orientation closely. The map of the tangential component has more distributed currents that are coherent with the chromospheric and coronal twisted structures. Moreover, it allows us to map and identify the direct and return currents in the sunspots. Finally, this decomposition of jzis general and can be applied to any vector magnetogram in order to better identify the weaker large-scale currents that are associated with coronal twisted/sheared structures. © 2014. The American Astronomical Society. All rights reserved..
format JOUR
author Gosain, S.
Démoulin, P.
López Fuentes, M.
author_facet Gosain, S.
Démoulin, P.
López Fuentes, M.
author_sort Gosain, S.
title Distribution of electric currents in sunspots from photosphere to corona
title_short Distribution of electric currents in sunspots from photosphere to corona
title_full Distribution of electric currents in sunspots from photosphere to corona
title_fullStr Distribution of electric currents in sunspots from photosphere to corona
title_full_unstemmed Distribution of electric currents in sunspots from photosphere to corona
title_sort distribution of electric currents in sunspots from photosphere to corona
url http://hdl.handle.net/20.500.12110/paper_0004637X_v793_n1_p_Gosain
work_keys_str_mv AT gosains distributionofelectriccurrentsinsunspotsfromphotospheretocorona
AT demoulinp distributionofelectriccurrentsinsunspotsfromphotospheretocorona
AT lopezfuentesm distributionofelectriccurrentsinsunspotsfromphotospheretocorona
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