Why are CMEs large-scale coronal events: Nature or nurture?

The apparent contradiction between small-scale source regions of, and large-scale coronal response to, coronal mass ejections (CMEs) has been a long-standing puzzle. For some, CMEs are considered to be inherently large-scale events ĝ€" eruptions in which a number of flux systems participate in...

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Autores principales: Van Driel-Gesztelyi, L., Attrill, G.D.R., Démoulin, P., Mandrini, C.H., Harra, L.K.
Formato: JOUR
Materias:
corona
magnetic field
numerical model
pressure effect
solar activity
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_09927689_v26_n10_p3077_VanDrielGesztelyi
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id todo:paper_09927689_v26_n10_p3077_VanDrielGesztelyi
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spelling todo:paper_09927689_v26_n10_p3077_VanDrielGesztelyi2023-10-03T15:55:42Z Why are CMEs large-scale coronal events: Nature or nurture? Van Driel-Gesztelyi, L. Attrill, G.D.R. Démoulin, P. Mandrini, C.H. Harra, L.K. corona magnetic field numerical model pressure effect solar activity The apparent contradiction between small-scale source regions of, and large-scale coronal response to, coronal mass ejections (CMEs) has been a long-standing puzzle. For some, CMEs are considered to be inherently large-scale events ĝ€" eruptions in which a number of flux systems participate in an unspecified manner, while others consider magnetic reconnection in special global topologies to be responsible for the large-scale response of the lower corona to CME events. Some of these ideas may indeed be correct in specific cases. However, what is the key element which makes CMEs large-scale? Observations show that the extent of the coronal disturbance matches the angular width of the CME ĝ€" an important clue, which does not feature strongly in any of the above suggestions. We review observational evidence for the large-scale nature of CME source regions and find them lacking. Then we compare different ideas regarding how CMEs evolve to become large-scale. The large-scale magnetic topology plays an important role in this process. There is amounting evidence, however, that the key process is magnetic reconnection between the CME and other magnetic structures. We outline a CME evolution model, which is able to account for all the key observational signatures of large-scale CMEs and presents a clear picture how large portions of the Sun become constituents of the CME. In this model reconnection is driven by the expansion of the CME core resulting from an over-pressure relative to the pressure in the CME's surroundings. This implies that the extent of the lower coronal signatures match the final angular width of the CME. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_09927689_v26_n10_p3077_VanDrielGesztelyi
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic corona
magnetic field
numerical model
pressure effect
solar activity
spellingShingle corona
magnetic field
numerical model
pressure effect
solar activity
Van Driel-Gesztelyi, L.
Attrill, G.D.R.
Démoulin, P.
Mandrini, C.H.
Harra, L.K.
Why are CMEs large-scale coronal events: Nature or nurture?
topic_facet corona
magnetic field
numerical model
pressure effect
solar activity
description The apparent contradiction between small-scale source regions of, and large-scale coronal response to, coronal mass ejections (CMEs) has been a long-standing puzzle. For some, CMEs are considered to be inherently large-scale events ĝ€" eruptions in which a number of flux systems participate in an unspecified manner, while others consider magnetic reconnection in special global topologies to be responsible for the large-scale response of the lower corona to CME events. Some of these ideas may indeed be correct in specific cases. However, what is the key element which makes CMEs large-scale? Observations show that the extent of the coronal disturbance matches the angular width of the CME ĝ€" an important clue, which does not feature strongly in any of the above suggestions. We review observational evidence for the large-scale nature of CME source regions and find them lacking. Then we compare different ideas regarding how CMEs evolve to become large-scale. The large-scale magnetic topology plays an important role in this process. There is amounting evidence, however, that the key process is magnetic reconnection between the CME and other magnetic structures. We outline a CME evolution model, which is able to account for all the key observational signatures of large-scale CMEs and presents a clear picture how large portions of the Sun become constituents of the CME. In this model reconnection is driven by the expansion of the CME core resulting from an over-pressure relative to the pressure in the CME's surroundings. This implies that the extent of the lower coronal signatures match the final angular width of the CME.
format JOUR
author Van Driel-Gesztelyi, L.
Attrill, G.D.R.
Démoulin, P.
Mandrini, C.H.
Harra, L.K.
author_facet Van Driel-Gesztelyi, L.
Attrill, G.D.R.
Démoulin, P.
Mandrini, C.H.
Harra, L.K.
author_sort Van Driel-Gesztelyi, L.
title Why are CMEs large-scale coronal events: Nature or nurture?
title_short Why are CMEs large-scale coronal events: Nature or nurture?
title_full Why are CMEs large-scale coronal events: Nature or nurture?
title_fullStr Why are CMEs large-scale coronal events: Nature or nurture?
title_full_unstemmed Why are CMEs large-scale coronal events: Nature or nurture?
title_sort why are cmes large-scale coronal events: nature or nurture?
url http://hdl.handle.net/20.500.12110/paper_09927689_v26_n10_p3077_VanDrielGesztelyi
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AT demoulinp whyarecmeslargescalecoronaleventsnatureornurture
AT mandrinich whyarecmeslargescalecoronaleventsnatureornurture
AT harralk whyarecmeslargescalecoronaleventsnatureornurture
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