Helicity loading and dissipation: The helicity budget of ar 7978 from the cradle to the grave

Through a multi-wavelength and multi-instrument analysis we evaluate the magnetic helicity budget of an isolated active region (NOAA 7978) from its emergence throughout its decay. Using Yohkoh/ SXT images and linear force-free magnetic extrapolations carried out on SOHO/MDI magnetograms, we compute...

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Publicado: 2002
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_09642749_v13_nC_p143_DrielGesztelyi
http://hdl.handle.net/20.500.12110/paper_09642749_v13_nC_p143_DrielGesztelyi
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id paper:paper_09642749_v13_nC_p143_DrielGesztelyi
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spelling paper:paper_09642749_v13_nC_p143_DrielGesztelyi2023-06-08T15:58:31Z Helicity loading and dissipation: The helicity budget of ar 7978 from the cradle to the grave Through a multi-wavelength and multi-instrument analysis we evaluate the magnetic helicity budget of an isolated active region (NOAA 7978) from its emergence throughout its decay. Using Yohkoh/ SXT images and linear force-free magnetic extrapolations carried out on SOHO/MDI magnetograms, we compute the relative magnetic helicity in the corona. Based on the observed magnetic field distribution we calculate the magnetic helicity injected by differential rotation. Then, using SOHO/LASCO & EIT and SXT images we identify all the 26 coronal mass ejections (CMEs) which originated from this active region during its lifetime and we estimate the amount of helicity which was shed via CMEs. Comparing these three values we find that the differential rotation can neither provide enough helicity to account for the diagnosed coronal helicity values, nor for the helicity carried away by CMEs. We suggest that the main source of the magnetic helicity must be the inherent twist of the magnetic flux tube forming the active region. © 2002 Elsevier B.V. All rights reserved. 2002 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_09642749_v13_nC_p143_DrielGesztelyi http://hdl.handle.net/20.500.12110/paper_09642749_v13_nC_p143_DrielGesztelyi
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
description Through a multi-wavelength and multi-instrument analysis we evaluate the magnetic helicity budget of an isolated active region (NOAA 7978) from its emergence throughout its decay. Using Yohkoh/ SXT images and linear force-free magnetic extrapolations carried out on SOHO/MDI magnetograms, we compute the relative magnetic helicity in the corona. Based on the observed magnetic field distribution we calculate the magnetic helicity injected by differential rotation. Then, using SOHO/LASCO & EIT and SXT images we identify all the 26 coronal mass ejections (CMEs) which originated from this active region during its lifetime and we estimate the amount of helicity which was shed via CMEs. Comparing these three values we find that the differential rotation can neither provide enough helicity to account for the diagnosed coronal helicity values, nor for the helicity carried away by CMEs. We suggest that the main source of the magnetic helicity must be the inherent twist of the magnetic flux tube forming the active region. © 2002 Elsevier B.V. All rights reserved.
title Helicity loading and dissipation: The helicity budget of ar 7978 from the cradle to the grave
spellingShingle Helicity loading and dissipation: The helicity budget of ar 7978 from the cradle to the grave
title_short Helicity loading and dissipation: The helicity budget of ar 7978 from the cradle to the grave
title_full Helicity loading and dissipation: The helicity budget of ar 7978 from the cradle to the grave
title_fullStr Helicity loading and dissipation: The helicity budget of ar 7978 from the cradle to the grave
title_full_unstemmed Helicity loading and dissipation: The helicity budget of ar 7978 from the cradle to the grave
title_sort helicity loading and dissipation: the helicity budget of ar 7978 from the cradle to the grave
publishDate 2002
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_09642749_v13_nC_p143_DrielGesztelyi
http://hdl.handle.net/20.500.12110/paper_09642749_v13_nC_p143_DrielGesztelyi
_version_ 1768543810065793024

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