Magnetic field and plasma scaling laws: Their implications for coronal heating models

Autores
Mandrini, Cristina Hemilse; Démoulin, Pascal; Klimchuk, James
Año de publicación
2000
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
In order to test different models of coronal heating, we have investigated how the magnetic field strength of coronal flux tubes depends on the end-to-end length of the tube. Using photospheric magnetograms from both observed and idealized active regions, we computed potential, linear force-free, and magnetostatic extrapolation models. For each model, we then determined the average coronal field strength, langBrang, in approximately 1000 individual flux tubes with regularly spaced footpoints. Scatter plots of langBrang versus length, L, are characterized by a flat section for small L and a steeply declining section for large L. They are well described by a function of the form log img1.gif = C1 + C2 log L + C3/2 log(L2 + S2), where C2 ≈ 0, -3 ≤ C3 ≤ -1, and 40 ≤ S ≤ 240 Mm is related to the characteristic size of the active region. There is a tendency for the magnitude of C3 to decrease as the magnetic complexity of the region increases. The average magnetic energy in a flux tube, langB2rang, exhibits a similar behavior, with only C3 being significantly different. For flux tubes of intermediate length, 50 ≤ L ≤ 300 Mm, corresponding to the soft X-ray loops in a study by Klimchuk & Porter (1995), we find a universal scaling law of the form img1.gif ∝ Lδ, where δ = -0.88 ± 0.3. By combining this with the Klimchuk & Porter result that the heating rate scales as L-2, we can test different models of coronal heating. We find that models involving the gradual stressing of the magnetic field, by slow footpoint motions, are in generally better agreement with the observational constraints than are wave heating models. We conclude, however, that the theoretical models must be more fully developed and the observational uncertainties must be reduced before any definitive statements about specific heating mechanisms can be made.
Fil: Mandrini, Cristina Hemilse. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentina
Fil: Démoulin, Pascal. Centre National de la Recherche Scientifique. Observatoire de Paris; Francia
Fil: Klimchuk, James. Spece Sciences División. Naval Research Laboratory; Estados Unidos
Materia
Magnetic Fields
Nivel de accesibilidad
acceso abierto
Condiciones de uso
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
Repositorio
CONICET Digital (CONICET)
Institución
Consejo Nacional de Investigaciones Científicas y Técnicas
OAI Identificador
oai:ri.conicet.gov.ar:11336/22626

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spelling Magnetic field and plasma scaling laws: Their implications for coronal heating modelsMandrini, Cristina HemilseDémoulin, PascalKlimchuk, JamesMagnetic Fieldshttps://purl.org/becyt/ford/1.3https://purl.org/becyt/ford/1In order to test different models of coronal heating, we have investigated how the magnetic field strength of coronal flux tubes depends on the end-to-end length of the tube. Using photospheric magnetograms from both observed and idealized active regions, we computed potential, linear force-free, and magnetostatic extrapolation models. For each model, we then determined the average coronal field strength, langBrang, in approximately 1000 individual flux tubes with regularly spaced footpoints. Scatter plots of langBrang versus length, L, are characterized by a flat section for small L and a steeply declining section for large L. They are well described by a function of the form log img1.gif = C1 + C2 log L + C3/2 log(L2 + S2), where C2 ≈ 0, -3 ≤ C3 ≤ -1, and 40 ≤ S ≤ 240 Mm is related to the characteristic size of the active region. There is a tendency for the magnitude of C3 to decrease as the magnetic complexity of the region increases. The average magnetic energy in a flux tube, langB2rang, exhibits a similar behavior, with only C3 being significantly different. For flux tubes of intermediate length, 50 ≤ L ≤ 300 Mm, corresponding to the soft X-ray loops in a study by Klimchuk & Porter (1995), we find a universal scaling law of the form img1.gif ∝ Lδ, where δ = -0.88 ± 0.3. By combining this with the Klimchuk & Porter result that the heating rate scales as L-2, we can test different models of coronal heating. We find that models involving the gradual stressing of the magnetic field, by slow footpoint motions, are in generally better agreement with the observational constraints than are wave heating models. We conclude, however, that the theoretical models must be more fully developed and the observational uncertainties must be reduced before any definitive statements about specific heating mechanisms can be made.Fil: Mandrini, Cristina Hemilse. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Démoulin, Pascal. Centre National de la Recherche Scientifique. Observatoire de Paris; FranciaFil: Klimchuk, James. Spece Sciences División. Naval Research Laboratory; Estados UnidosIOP Publishing2000-12info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionhttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfapplication/pdfhttp://hdl.handle.net/11336/22626Mandrini, Cristina Hemilse; Démoulin, Pascal; Klimchuk, James; Magnetic field and plasma scaling laws: Their implications for coronal heating models; IOP Publishing; Astrophysical Journal; 530; 2; 12-2000; 999-10150004-637XCONICET DigitalCONICETenginfo:eu-repo/semantics/altIdentifier/url/http://iopscience.iop.org/article/10.1086/308398/metainfo:eu-repo/semantics/altIdentifier/doi/10.1086/308398info:eu-repo/semantics/openAccesshttps://creativecommons.org/licenses/by-nc-sa/2.5/ar/reponame:CONICET Digital (CONICET)instname:Consejo Nacional de Investigaciones Científicas y Técnicas2025-09-29T10:21:29Zoai:ri.conicet.gov.ar:11336/22626instacron:CONICETInstitucionalhttp://ri.conicet.gov.ar/Organismo científico-tecnológicoNo correspondehttp://ri.conicet.gov.ar/oai/requestdasensio@conicet.gov.ar; lcarlino@conicet.gov.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:34982025-09-29 10:21:29.798CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicasfalse
dc.title.none.fl_str_mv Magnetic field and plasma scaling laws: Their implications for coronal heating models
title Magnetic field and plasma scaling laws: Their implications for coronal heating models
spellingShingle Magnetic field and plasma scaling laws: Their implications for coronal heating models
Mandrini, Cristina Hemilse
Magnetic Fields
title_short Magnetic field and plasma scaling laws: Their implications for coronal heating models
title_full Magnetic field and plasma scaling laws: Their implications for coronal heating models
title_fullStr Magnetic field and plasma scaling laws: Their implications for coronal heating models
title_full_unstemmed Magnetic field and plasma scaling laws: Their implications for coronal heating models
title_sort Magnetic field and plasma scaling laws: Their implications for coronal heating models
dc.creator.none.fl_str_mv Mandrini, Cristina Hemilse
Démoulin, Pascal
Klimchuk, James
author Mandrini, Cristina Hemilse
author_facet Mandrini, Cristina Hemilse
Démoulin, Pascal
Klimchuk, James
author_role author
author2 Démoulin, Pascal
Klimchuk, James
author2_role author
author
dc.subject.none.fl_str_mv Magnetic Fields
topic Magnetic Fields
purl_subject.fl_str_mv https://purl.org/becyt/ford/1.3
https://purl.org/becyt/ford/1
dc.description.none.fl_txt_mv In order to test different models of coronal heating, we have investigated how the magnetic field strength of coronal flux tubes depends on the end-to-end length of the tube. Using photospheric magnetograms from both observed and idealized active regions, we computed potential, linear force-free, and magnetostatic extrapolation models. For each model, we then determined the average coronal field strength, langBrang, in approximately 1000 individual flux tubes with regularly spaced footpoints. Scatter plots of langBrang versus length, L, are characterized by a flat section for small L and a steeply declining section for large L. They are well described by a function of the form log img1.gif = C1 + C2 log L + C3/2 log(L2 + S2), where C2 ≈ 0, -3 ≤ C3 ≤ -1, and 40 ≤ S ≤ 240 Mm is related to the characteristic size of the active region. There is a tendency for the magnitude of C3 to decrease as the magnetic complexity of the region increases. The average magnetic energy in a flux tube, langB2rang, exhibits a similar behavior, with only C3 being significantly different. For flux tubes of intermediate length, 50 ≤ L ≤ 300 Mm, corresponding to the soft X-ray loops in a study by Klimchuk & Porter (1995), we find a universal scaling law of the form img1.gif ∝ Lδ, where δ = -0.88 ± 0.3. By combining this with the Klimchuk & Porter result that the heating rate scales as L-2, we can test different models of coronal heating. We find that models involving the gradual stressing of the magnetic field, by slow footpoint motions, are in generally better agreement with the observational constraints than are wave heating models. We conclude, however, that the theoretical models must be more fully developed and the observational uncertainties must be reduced before any definitive statements about specific heating mechanisms can be made.
Fil: Mandrini, Cristina Hemilse. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentina
Fil: Démoulin, Pascal. Centre National de la Recherche Scientifique. Observatoire de Paris; Francia
Fil: Klimchuk, James. Spece Sciences División. Naval Research Laboratory; Estados Unidos
description In order to test different models of coronal heating, we have investigated how the magnetic field strength of coronal flux tubes depends on the end-to-end length of the tube. Using photospheric magnetograms from both observed and idealized active regions, we computed potential, linear force-free, and magnetostatic extrapolation models. For each model, we then determined the average coronal field strength, langBrang, in approximately 1000 individual flux tubes with regularly spaced footpoints. Scatter plots of langBrang versus length, L, are characterized by a flat section for small L and a steeply declining section for large L. They are well described by a function of the form log img1.gif = C1 + C2 log L + C3/2 log(L2 + S2), where C2 ≈ 0, -3 ≤ C3 ≤ -1, and 40 ≤ S ≤ 240 Mm is related to the characteristic size of the active region. There is a tendency for the magnitude of C3 to decrease as the magnetic complexity of the region increases. The average magnetic energy in a flux tube, langB2rang, exhibits a similar behavior, with only C3 being significantly different. For flux tubes of intermediate length, 50 ≤ L ≤ 300 Mm, corresponding to the soft X-ray loops in a study by Klimchuk & Porter (1995), we find a universal scaling law of the form img1.gif ∝ Lδ, where δ = -0.88 ± 0.3. By combining this with the Klimchuk & Porter result that the heating rate scales as L-2, we can test different models of coronal heating. We find that models involving the gradual stressing of the magnetic field, by slow footpoint motions, are in generally better agreement with the observational constraints than are wave heating models. We conclude, however, that the theoretical models must be more fully developed and the observational uncertainties must be reduced before any definitive statements about specific heating mechanisms can be made.
publishDate 2000
dc.date.none.fl_str_mv 2000-12
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
http://purl.org/coar/resource_type/c_6501
info:ar-repo/semantics/articulo
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://hdl.handle.net/11336/22626
Mandrini, Cristina Hemilse; Démoulin, Pascal; Klimchuk, James; Magnetic field and plasma scaling laws: Their implications for coronal heating models; IOP Publishing; Astrophysical Journal; 530; 2; 12-2000; 999-1015
0004-637X
CONICET Digital
CONICET
url http://hdl.handle.net/11336/22626
identifier_str_mv Mandrini, Cristina Hemilse; Démoulin, Pascal; Klimchuk, James; Magnetic field and plasma scaling laws: Their implications for coronal heating models; IOP Publishing; Astrophysical Journal; 530; 2; 12-2000; 999-1015
0004-637X
CONICET Digital
CONICET
dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/url/http://iopscience.iop.org/article/10.1086/308398/meta
info:eu-repo/semantics/altIdentifier/doi/10.1086/308398
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
eu_rights_str_mv openAccess
rights_invalid_str_mv https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
dc.format.none.fl_str_mv application/pdf
application/pdf
dc.publisher.none.fl_str_mv IOP Publishing
publisher.none.fl_str_mv IOP Publishing
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