3D magnetic reconnection at an X-ray bright point

On May 1, 1993, a flaring X-ray bright point (XBP) was observed for about 16 hours in the old, disintegrating, bipolar active region (AR) NOAA 7493. During this period, a minor magnetic bipole (1020 Mx) emerged in the region. We have found observational evidence showing that the XBP brightenings wer...

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Autores principales: Mandrini, C.H., Démoulin, P., Van Driel-Gesztelyi, L., Schmieder, B., Cauzzi, G., Hofmann, A.
Formato: JOUR
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_00380938_v168_n1_p115_Mandrini
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
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spelling todo:paper_00380938_v168_n1_p115_Mandrini2023-10-03T14:48:27Z 3D magnetic reconnection at an X-ray bright point Mandrini, C.H. Démoulin, P. Van Driel-Gesztelyi, L. Schmieder, B. Cauzzi, G. Hofmann, A. On May 1, 1993, a flaring X-ray bright point (XBP) was observed for about 16 hours in the old, disintegrating, bipolar active region (AR) NOAA 7493. During this period, a minor magnetic bipole (1020 Mx) emerged in the region. We have found observational evidence showing that the XBP brightenings were due to magnetic reconnection between the new bipole and pre-existing plage fields. The aim of the present work is to substantiate with magnetic modelling what has been shown by the observations. For this purpose we extrapolate the observed photospheric magnetic fields in the linear force-free approximation and follow its evolution during the lifetime of the XBP. From the computed coronal field lines we determine the location of regions of drastic change in field-line linkage, called 'quasi-separatrix layers' or QSLs. QSLs arc open layers that behave physically like separatrices: the break down of ideal magnetohydrodynamics and the release of free magnetic energy may occur at these locations when their thickness is small enough. The extrapolated field lines, with photospheric footpoints on both sides of QSLs, match the observed chromospheric and coronal structures (arch filament system, XBP and faint X-ray loops (FXL)). We study also the evolution of the width of the QSL located over the new negative polarity pore: the calculated QSL is very thin (typically less than 100 m) during the lifetime of the XBP, but becomes much thicker (≥ 104 m) after the XBP has faded. Furthermore we show that peaks in X-ray brightness propagate along the FXL with a velocity of ≈ 670 km s-1, starting from the XBP location, implying that the energy is released where the emerging bipole impacts against pre-existing coronal loops. We discuss the possible mechanism of energy transport and conclude that the energy is conducted to the remote footpoints of the FXL by a thermal front. These results strongly support the supposition that the XBP brightness and flaring are due to the interaction of different flux systems, through 3D magnetic reconnection, at QSLs. © 1996 Kluwer Academic Publishers. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_00380938_v168_n1_p115_Mandrini
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
description On May 1, 1993, a flaring X-ray bright point (XBP) was observed for about 16 hours in the old, disintegrating, bipolar active region (AR) NOAA 7493. During this period, a minor magnetic bipole (1020 Mx) emerged in the region. We have found observational evidence showing that the XBP brightenings were due to magnetic reconnection between the new bipole and pre-existing plage fields. The aim of the present work is to substantiate with magnetic modelling what has been shown by the observations. For this purpose we extrapolate the observed photospheric magnetic fields in the linear force-free approximation and follow its evolution during the lifetime of the XBP. From the computed coronal field lines we determine the location of regions of drastic change in field-line linkage, called 'quasi-separatrix layers' or QSLs. QSLs arc open layers that behave physically like separatrices: the break down of ideal magnetohydrodynamics and the release of free magnetic energy may occur at these locations when their thickness is small enough. The extrapolated field lines, with photospheric footpoints on both sides of QSLs, match the observed chromospheric and coronal structures (arch filament system, XBP and faint X-ray loops (FXL)). We study also the evolution of the width of the QSL located over the new negative polarity pore: the calculated QSL is very thin (typically less than 100 m) during the lifetime of the XBP, but becomes much thicker (≥ 104 m) after the XBP has faded. Furthermore we show that peaks in X-ray brightness propagate along the FXL with a velocity of ≈ 670 km s-1, starting from the XBP location, implying that the energy is released where the emerging bipole impacts against pre-existing coronal loops. We discuss the possible mechanism of energy transport and conclude that the energy is conducted to the remote footpoints of the FXL by a thermal front. These results strongly support the supposition that the XBP brightness and flaring are due to the interaction of different flux systems, through 3D magnetic reconnection, at QSLs. © 1996 Kluwer Academic Publishers.
format JOUR
author Mandrini, C.H.
Démoulin, P.
Van Driel-Gesztelyi, L.
Schmieder, B.
Cauzzi, G.
Hofmann, A.
spellingShingle Mandrini, C.H.
Démoulin, P.
Van Driel-Gesztelyi, L.
Schmieder, B.
Cauzzi, G.
Hofmann, A.
3D magnetic reconnection at an X-ray bright point
author_facet Mandrini, C.H.
Démoulin, P.
Van Driel-Gesztelyi, L.
Schmieder, B.
Cauzzi, G.
Hofmann, A.
author_sort Mandrini, C.H.
title 3D magnetic reconnection at an X-ray bright point
title_short 3D magnetic reconnection at an X-ray bright point
title_full 3D magnetic reconnection at an X-ray bright point
title_fullStr 3D magnetic reconnection at an X-ray bright point
title_full_unstemmed 3D magnetic reconnection at an X-ray bright point
title_sort 3d magnetic reconnection at an x-ray bright point
url http://hdl.handle.net/20.500.12110/paper_00380938_v168_n1_p115_Mandrini
work_keys_str_mv AT mandrinich 3dmagneticreconnectionatanxraybrightpoint
AT demoulinp 3dmagneticreconnectionatanxraybrightpoint
AT vandrielgesztelyil 3dmagneticreconnectionatanxraybrightpoint
AT schmiederb 3dmagneticreconnectionatanxraybrightpoint
AT cauzzig 3dmagneticreconnectionatanxraybrightpoint
AT hofmanna 3dmagneticreconnectionatanxraybrightpoint
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