Solar coronal heating: AC versus DC

The heating of the plasma confined in active regions of the solar corona is caused by the dissipation of magnetic stresses induced by the photospheric motions of the loop footpoints. The aim of the present paper is to analyze whether solar coronal heating is dominated by slow (DC) or rapid (AC) phot...

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Autores principales: Milano, L.J., Gómez, D.O., Martens, P.C.
Formato: JOUR
Materias:
MHD
Sun: Corona
Turbulence
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_0004637X_v490_n1PARTI_p442_Milano
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
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spelling todo:paper_0004637X_v490_n1PARTI_p442_Milano2023-10-03T14:01:43Z Solar coronal heating: AC versus DC Milano, L.J. Gómez, D.O. Martens, P.C. MHD Sun: Corona Turbulence The heating of the plasma confined in active regions of the solar corona is caused by the dissipation of magnetic stresses induced by the photospheric motions of the loop footpoints. The aim of the present paper is to analyze whether solar coronal heating is dominated by slow (DC) or rapid (AC) photospheric driving motions. We describe the dynamics of a coronal loop through the reduced magnetohydrodynamic equations and assume a fully turbulent state in the coronal plasma. The boundary condition for these equations is the subphotospheric velocity field that stresses the magnetic field lines, thus replenishing the magnetic energy that is continuously being dissipated inside the corona. In a turbulent scenario, energy is efficiently transferred by a direct cascade to the microscale, where viscous and Joule dissipation take place. Therefore, for the macroscopic dynamics of the fields, the net effect of turbulence is to produce a dramatic enhancement of the dissipation rate. This effect of the microscale on the macroscale is modeled through effective dissipation coefficients much larger than the molecular ones. We consistently integrate the large-scale evolution of a coronal loop and compute the effective dissipation coefficients by applying a closure model (the eddy-damped, quasi-normal Markovian approximation). For broadband power-law photospheric power spectra, the heating of coronal loops is DC dominated. Nonetheless, a better knowledge of the photospheric power spectrum as a function of both frequency and wavenumber will allow for more accurate predictions of the heating rate from this simple model. © 1997. 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_v490_n1PARTI_p442_Milano
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic MHD
Sun: Corona
Turbulence
spellingShingle MHD
Sun: Corona
Turbulence
Milano, L.J.
Gómez, D.O.
Martens, P.C.
Solar coronal heating: AC versus DC
topic_facet MHD
Sun: Corona
Turbulence
description The heating of the plasma confined in active regions of the solar corona is caused by the dissipation of magnetic stresses induced by the photospheric motions of the loop footpoints. The aim of the present paper is to analyze whether solar coronal heating is dominated by slow (DC) or rapid (AC) photospheric driving motions. We describe the dynamics of a coronal loop through the reduced magnetohydrodynamic equations and assume a fully turbulent state in the coronal plasma. The boundary condition for these equations is the subphotospheric velocity field that stresses the magnetic field lines, thus replenishing the magnetic energy that is continuously being dissipated inside the corona. In a turbulent scenario, energy is efficiently transferred by a direct cascade to the microscale, where viscous and Joule dissipation take place. Therefore, for the macroscopic dynamics of the fields, the net effect of turbulence is to produce a dramatic enhancement of the dissipation rate. This effect of the microscale on the macroscale is modeled through effective dissipation coefficients much larger than the molecular ones. We consistently integrate the large-scale evolution of a coronal loop and compute the effective dissipation coefficients by applying a closure model (the eddy-damped, quasi-normal Markovian approximation). For broadband power-law photospheric power spectra, the heating of coronal loops is DC dominated. Nonetheless, a better knowledge of the photospheric power spectrum as a function of both frequency and wavenumber will allow for more accurate predictions of the heating rate from this simple model. © 1997. The American Astronomical Society. All rights reserved.
format JOUR
author Milano, L.J.
Gómez, D.O.
Martens, P.C.
author_facet Milano, L.J.
Gómez, D.O.
Martens, P.C.
author_sort Milano, L.J.
title Solar coronal heating: AC versus DC
title_short Solar coronal heating: AC versus DC
title_full Solar coronal heating: AC versus DC
title_fullStr Solar coronal heating: AC versus DC
title_full_unstemmed Solar coronal heating: AC versus DC
title_sort solar coronal heating: ac versus dc
url http://hdl.handle.net/20.500.12110/paper_0004637X_v490_n1PARTI_p442_Milano
work_keys_str_mv AT milanolj solarcoronalheatingacversusdc
AT gomezdo solarcoronalheatingacversusdc
AT martenspc solarcoronalheatingacversusdc
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