A model solar flares and their homologous behavior
A model describing physical processes of solar flares and their homologous behavior is presented based on resistive MHD simulations of magnetic arcade evolution subject to continuous shear-increasing footpoint motions. It is proposed in the model that the individual flaring process encompasses magne...
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ftosti:oai:osti.gov:750430 2023-07-30T04:07:32+02:00 A model solar flares and their homologous behavior Choe, G.S. Cheng, C.Z. 2008-02-05 application/pdf http://www.osti.gov/servlets/purl/750430 https://www.osti.gov/biblio/750430 https://doi.org/10.2172/750430 unknown http://www.osti.gov/servlets/purl/750430 https://www.osti.gov/biblio/750430 https://doi.org/10.2172/750430 doi:10.2172/750430 66 PHYSICS SOLAR FLARES MATHEMATICAL MODELS MAGNETOHYDRODYNAMICS MAGNETIC RECONNECTION MAGNETIC ISLANDS SHEAR 2008 ftosti https://doi.org/10.2172/750430 2023-07-11T08:36:14Z A model describing physical processes of solar flares and their homologous behavior is presented based on resistive MHD simulations of magnetic arcade evolution subject to continuous shear-increasing footpoint motions. It is proposed in the model that the individual flaring process encompasses magnetic reconnection of arcade field lines, generation of magnetic islands in the magnetic arcade, and coalescence of magnetic islands. When a magnetic arcade is sheared, a current sheet is formed and magnetic reconnection can take place to form a magnetic island. A continuing increase of magnetic shear can trigger a new reconnection process and create another island in the underlying arcade below the magnetic island. The newborn island rises faster than the preceding island and merges with it to form one island. Before merging with the upper island is completed, the newborn island exhibits two different phases of rising motion: the first phase with a slower rising speed and the second phase wit h a faster rising speed. This is consistent with the Yohkoh observation by Ohyama and Shibata (1998) of X-ray plasma ejecta motion. The first phase, in which reconnection of line-tied field in the underlying arcade is important, can be regarded to be related with the preflare phase. In the second phase, the island coalescence takes place, which creates an elongated current sheet below and enhances the reconnection rate of the line-tied arcade field. This phase is interpreted as the impulsive phase or the flash phase of flares. The obtained reconnection electric field is large enough to accelerate electrons to an energy level higher than 10 keV, which is necessary for observed X-ray emissions. After merging of the islands is completed, magnetic reconnection continues in the current sheet under the integrated island for rather a long period, which can be considered as the main phase of flares. The sequence of all these processes is repeated with some time interval while a shear-increasing motion continues. The authors propose that a ... Other/Unknown Material Magnetic Island Upper Island SciTec Connect (Office of Scientific and Technical Information - OSTI, U.S. Department of Energy) Magnetic Island ENVELOPE(77.909,77.909,-68.543,-68.543) |
institution |
Open Polar |
collection |
SciTec Connect (Office of Scientific and Technical Information - OSTI, U.S. Department of Energy) |
op_collection_id |
ftosti |
language |
unknown |
topic |
66 PHYSICS SOLAR FLARES MATHEMATICAL MODELS MAGNETOHYDRODYNAMICS MAGNETIC RECONNECTION MAGNETIC ISLANDS SHEAR |
spellingShingle |
66 PHYSICS SOLAR FLARES MATHEMATICAL MODELS MAGNETOHYDRODYNAMICS MAGNETIC RECONNECTION MAGNETIC ISLANDS SHEAR Choe, G.S. Cheng, C.Z. A model solar flares and their homologous behavior |
topic_facet |
66 PHYSICS SOLAR FLARES MATHEMATICAL MODELS MAGNETOHYDRODYNAMICS MAGNETIC RECONNECTION MAGNETIC ISLANDS SHEAR |
description |
A model describing physical processes of solar flares and their homologous behavior is presented based on resistive MHD simulations of magnetic arcade evolution subject to continuous shear-increasing footpoint motions. It is proposed in the model that the individual flaring process encompasses magnetic reconnection of arcade field lines, generation of magnetic islands in the magnetic arcade, and coalescence of magnetic islands. When a magnetic arcade is sheared, a current sheet is formed and magnetic reconnection can take place to form a magnetic island. A continuing increase of magnetic shear can trigger a new reconnection process and create another island in the underlying arcade below the magnetic island. The newborn island rises faster than the preceding island and merges with it to form one island. Before merging with the upper island is completed, the newborn island exhibits two different phases of rising motion: the first phase with a slower rising speed and the second phase wit h a faster rising speed. This is consistent with the Yohkoh observation by Ohyama and Shibata (1998) of X-ray plasma ejecta motion. The first phase, in which reconnection of line-tied field in the underlying arcade is important, can be regarded to be related with the preflare phase. In the second phase, the island coalescence takes place, which creates an elongated current sheet below and enhances the reconnection rate of the line-tied arcade field. This phase is interpreted as the impulsive phase or the flash phase of flares. The obtained reconnection electric field is large enough to accelerate electrons to an energy level higher than 10 keV, which is necessary for observed X-ray emissions. After merging of the islands is completed, magnetic reconnection continues in the current sheet under the integrated island for rather a long period, which can be considered as the main phase of flares. The sequence of all these processes is repeated with some time interval while a shear-increasing motion continues. The authors propose that a ... |
author |
Choe, G.S. Cheng, C.Z. |
author_facet |
Choe, G.S. Cheng, C.Z. |
author_sort |
Choe, G.S. |
title |
A model solar flares and their homologous behavior |
title_short |
A model solar flares and their homologous behavior |
title_full |
A model solar flares and their homologous behavior |
title_fullStr |
A model solar flares and their homologous behavior |
title_full_unstemmed |
A model solar flares and their homologous behavior |
title_sort |
model solar flares and their homologous behavior |
publishDate |
2008 |
url |
http://www.osti.gov/servlets/purl/750430 https://www.osti.gov/biblio/750430 https://doi.org/10.2172/750430 |
long_lat |
ENVELOPE(77.909,77.909,-68.543,-68.543) |
geographic |
Magnetic Island |
geographic_facet |
Magnetic Island |
genre |
Magnetic Island Upper Island |
genre_facet |
Magnetic Island Upper Island |
op_relation |
http://www.osti.gov/servlets/purl/750430 https://www.osti.gov/biblio/750430 https://doi.org/10.2172/750430 doi:10.2172/750430 |
op_doi |
https://doi.org/10.2172/750430 |
_version_ |
1772820926133436416 |