Hopf bifurcations in coronal loops I. Stability conditions for static equilibrium

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We study the coupling between the hot plasma confined in a coronal loop and the much colder chromospheric plasma at the footpoints. Considering the coronal heating rate as a control parameter, we find that the static equilibrium becomes unstable for heating rates below a critical value, giving rise...

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Autores principales:	Gómez, D., Sicardi Schifino, A., Ferro Fontán, C.
Formato:	Artículo publishedVersion
Publicado:	1990
Materias:	Hydromagnetics Sun: corona
Acceso en línea:	http://hdl.handle.net/20.500.12110/paper_0004637X_v352_n1_p318_Gomez https://repositoriouba.sisbi.uba.ar/gsdl/cgi-bin/library.cgi?a=d&c=artiaex&d=paper_0004637X_v352_n1_p318_Gomez_oai
Aporte de:	Repositorio Digital de la Universidad de Buenos Aires (UBA) de Universidad de Buenos Aires

id	I28-R145-paper_0004637X_v352_n1_p318_Gomez_oai
record_format	dspace
spelling	I28-R145-paper_0004637X_v352_n1_p318_Gomez_oai2024-08-16 Gómez, D. Sicardi Schifino, A. Ferro Fontán, C. 1990 We study the coupling between the hot plasma confined in a coronal loop and the much colder chromospheric plasma at the footpoints. Considering the coronal heating rate as a control parameter, we find that the static equilibrium becomes unstable for heating rates below a critical value, giving rise to the appearance of a stable limit cycle. Starting from the hydrodynamic equations, we derive a model which generalizes the analysis of Kuin and Martens and consistently takes into account the condensation-evaporation process. In this paper, we linearize our equations in order to find the bifurcation point where the stability of the static equilibrium is lost. We also show that this model can provide a natural explanation for the excess widths of EUV spectral lines formed in the transition region. Moreover, we can predict the observed reduction in the broadening of these lines when they form in certain active regions, like quiescent prominences or sunspots. Fil:Gómez, D. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Sicardi Schifino, A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Ferro Fontán, C. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. application/pdf http://hdl.handle.net/20.500.12110/paper_0004637X_v352_n1_p318_Gomez info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar Astrophys. J. 1990;352(1):318-325 Hydromagnetics Sun: corona Hopf bifurcations in coronal loops I. Stability conditions for static equilibrium info:eu-repo/semantics/article info:ar-repo/semantics/artículo info:eu-repo/semantics/publishedVersion https://repositoriouba.sisbi.uba.ar/gsdl/cgi-bin/library.cgi?a=d&c=artiaex&d=paper_0004637X_v352_n1_p318_Gomez_oai
institution	Universidad de Buenos Aires
institution_str	I-28
repository_str	R-145
collection	Repositorio Digital de la Universidad de Buenos Aires (UBA)
topic	Hydromagnetics Sun: corona
spellingShingle	Hydromagnetics Sun: corona Gómez, D. Sicardi Schifino, A. Ferro Fontán, C. Hopf bifurcations in coronal loops I. Stability conditions for static equilibrium
topic_facet	Hydromagnetics Sun: corona
description	We study the coupling between the hot plasma confined in a coronal loop and the much colder chromospheric plasma at the footpoints. Considering the coronal heating rate as a control parameter, we find that the static equilibrium becomes unstable for heating rates below a critical value, giving rise to the appearance of a stable limit cycle. Starting from the hydrodynamic equations, we derive a model which generalizes the analysis of Kuin and Martens and consistently takes into account the condensation-evaporation process. In this paper, we linearize our equations in order to find the bifurcation point where the stability of the static equilibrium is lost. We also show that this model can provide a natural explanation for the excess widths of EUV spectral lines formed in the transition region. Moreover, we can predict the observed reduction in the broadening of these lines when they form in certain active regions, like quiescent prominences or sunspots.
format	Artículo Artículo publishedVersion
author	Gómez, D. Sicardi Schifino, A. Ferro Fontán, C.
author_facet	Gómez, D. Sicardi Schifino, A. Ferro Fontán, C.
author_sort	Gómez, D.
title	Hopf bifurcations in coronal loops I. Stability conditions for static equilibrium
title_short	Hopf bifurcations in coronal loops I. Stability conditions for static equilibrium
title_full	Hopf bifurcations in coronal loops I. Stability conditions for static equilibrium
title_fullStr	Hopf bifurcations in coronal loops I. Stability conditions for static equilibrium
title_full_unstemmed	Hopf bifurcations in coronal loops I. Stability conditions for static equilibrium
title_sort	hopf bifurcations in coronal loops i. stability conditions for static equilibrium
publishDate	1990
url	http://hdl.handle.net/20.500.12110/paper_0004637X_v352_n1_p318_Gomez https://repositoriouba.sisbi.uba.ar/gsdl/cgi-bin/library.cgi?a=d&c=artiaex&d=paper_0004637X_v352_n1_p318_Gomez_oai
work_keys_str_mv	AT gomezd hopfbifurcationsincoronalloopsistabilityconditionsforstaticequilibrium AT sicardischifinoa hopfbifurcationsincoronalloopsistabilityconditionsforstaticequilibrium AT ferrofontanc hopfbifurcationsincoronalloopsistabilityconditionsforstaticequilibrium
_version_	1809357187034644480

Hopf bifurcations in coronal loops I. Stability conditions for static equilibrium

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