Parallel evolution of quasi-separatrix layers and active region upflows

Persistent plasma upflows were observed with Hinode's EUV Imaging Spectrometer (EIS) at the edges of active region (AR) 10978 as it crossed the solar disk. We analyze the evolution of the photospheric magnetic and velocity fields of the AR, model its coronal magnetic field, and compute the loca...

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Autores principales:	Cristiani, German Diego, Nuevo, Federico Alberto, Vasquez, Alberto Marcos
Publicado:	2015
Materias:	Sun: atmosphere Sun: corona Sun: magnetic fields
Acceso en línea:	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_0004637X_v809_n1_p_Mandrini http://hdl.handle.net/20.500.12110/paper_0004637X_v809_n1_p_Mandrini
Aporte de:	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires

id	paper:paper_0004637X_v809_n1_p_Mandrini
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spelling	paper:paper_0004637X_v809_n1_p_Mandrini2023-06-08T14:29:15Z Parallel evolution of quasi-separatrix layers and active region upflows Cristiani, German Diego Nuevo, Federico Alberto Vasquez, Alberto Marcos Sun: atmosphere Sun: corona Sun: magnetic fields Persistent plasma upflows were observed with Hinode's EUV Imaging Spectrometer (EIS) at the edges of active region (AR) 10978 as it crossed the solar disk. We analyze the evolution of the photospheric magnetic and velocity fields of the AR, model its coronal magnetic field, and compute the location of magnetic null-points and quasi-sepratrix layers (QSLs) searching for the origin of EIS upflows. Magnetic reconnection at the computed null points cannot explain all of the observed EIS upflow regions. However, EIS upflows and QSLs are found to evolve in parallel, both temporarily and spatially. Sections of two sets of QSLs, called outer and inner, are found associated to EIS upflow streams having different characteristics. The reconnection process in the outer QSLs is forced by a large-scale photospheric flow pattern, which is present in the AR for several days. We propose a scenario in which upflows are observed, provided that a large enough asymmetry in plasma pressure exists between the pre-reconnection loops and lasts as long as a photospheric forcing is at work. A similar mechanism operates in the inner QSLs; in this case, it is forced by the emergence and evolution of the bipoles between the two main AR polarities. Our findings provide strong support for the results from previous individual case studies investigating the role of magnetic reconnection at QSLs as the origin of the upflowing plasma. Furthermore, we propose that persistent reconnection along QSLs does not only drive the EIS upflows, but is also responsible for the continuous metric radio noise-storm observed in AR 10978 along its disk transit by the Nançay Radio Heliograph. © 2015. The American Astronomical Society. All rights reserved.. Fil:Cristiani, G.D. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Nuevo, F.A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Vásquez, A.M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2015 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_0004637X_v809_n1_p_Mandrini http://hdl.handle.net/20.500.12110/paper_0004637X_v809_n1_p_Mandrini
institution	Universidad de Buenos Aires
institution_str	I-28
repository_str	R-134
collection	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic	Sun: atmosphere Sun: corona Sun: magnetic fields
spellingShingle	Sun: atmosphere Sun: corona Sun: magnetic fields Cristiani, German Diego Nuevo, Federico Alberto Vasquez, Alberto Marcos Parallel evolution of quasi-separatrix layers and active region upflows
topic_facet	Sun: atmosphere Sun: corona Sun: magnetic fields
description	Persistent plasma upflows were observed with Hinode's EUV Imaging Spectrometer (EIS) at the edges of active region (AR) 10978 as it crossed the solar disk. We analyze the evolution of the photospheric magnetic and velocity fields of the AR, model its coronal magnetic field, and compute the location of magnetic null-points and quasi-sepratrix layers (QSLs) searching for the origin of EIS upflows. Magnetic reconnection at the computed null points cannot explain all of the observed EIS upflow regions. However, EIS upflows and QSLs are found to evolve in parallel, both temporarily and spatially. Sections of two sets of QSLs, called outer and inner, are found associated to EIS upflow streams having different characteristics. The reconnection process in the outer QSLs is forced by a large-scale photospheric flow pattern, which is present in the AR for several days. We propose a scenario in which upflows are observed, provided that a large enough asymmetry in plasma pressure exists between the pre-reconnection loops and lasts as long as a photospheric forcing is at work. A similar mechanism operates in the inner QSLs; in this case, it is forced by the emergence and evolution of the bipoles between the two main AR polarities. Our findings provide strong support for the results from previous individual case studies investigating the role of magnetic reconnection at QSLs as the origin of the upflowing plasma. Furthermore, we propose that persistent reconnection along QSLs does not only drive the EIS upflows, but is also responsible for the continuous metric radio noise-storm observed in AR 10978 along its disk transit by the Nançay Radio Heliograph. © 2015. The American Astronomical Society. All rights reserved..
author	Cristiani, German Diego Nuevo, Federico Alberto Vasquez, Alberto Marcos
author_facet	Cristiani, German Diego Nuevo, Federico Alberto Vasquez, Alberto Marcos
author_sort	Cristiani, German Diego
title	Parallel evolution of quasi-separatrix layers and active region upflows
title_short	Parallel evolution of quasi-separatrix layers and active region upflows
title_full	Parallel evolution of quasi-separatrix layers and active region upflows
title_fullStr	Parallel evolution of quasi-separatrix layers and active region upflows
title_full_unstemmed	Parallel evolution of quasi-separatrix layers and active region upflows
title_sort	parallel evolution of quasi-separatrix layers and active region upflows
publishDate	2015
url	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_0004637X_v809_n1_p_Mandrini http://hdl.handle.net/20.500.12110/paper_0004637X_v809_n1_p_Mandrini
work_keys_str_mv	AT cristianigermandiego parallelevolutionofquasiseparatrixlayersandactiveregionupflows AT nuevofedericoalberto parallelevolutionofquasiseparatrixlayersandactiveregionupflows AT vasquezalbertomarcos parallelevolutionofquasiseparatrixlayersandactiveregionupflows
_version_	1768544847731359744

Parallel evolution of quasi-separatrix layers and active region upflows

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