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Preflare magnetic and velocity fieldsA characterization is given of the preflare magnetic field, using theoretical models of force free fields together with observed field structure to determine the general morphology. Direct observational evidence for sheared magnetic fields is presented. The role of this magnetic shear in the flare process is considered within the context of a MHD model that describes the buildup of magnetic energy, and the concept of a critical value of shear is explored. The related subject of electric currents in the preflare state is discussed next, with emphasis on new insights provided by direct calculations of the vertical electric current density from vector magnetograph data and on the role of these currents in producing preflare brightenings. Results from investigations concerning velocity fields in flaring active regions, describing observations and analyses of preflare ejecta, sheared velocities, and vortical motions near flaring sites are given. This is followed by a critical review of prevalent concepts concerning the association of flux emergence with flares
Document ID
19870009897
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Hagyard, M. J. (NASA Marshall Space Flight Center Huntsville, Ala., United States)
Gaizauskas, V. (Herzberg Inst. of Astrophysics Ottawa, Ontario, Canada)
Chapman, G. A. (California State Univ. Fullerton, United States)
Deloach, A. C. (NASA Marshall Space Flight Center Huntsville, Ala., United States)
Gary, G. A. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Jones, H. P. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Karpen, J. T. (Naval Research Lab. Washington, D. C., United States)
Martres, M.-J. (Observatoire de Paris France)
Porter, J. G. (NASA Marshall Space Flight Center Huntsville, Ala., United States)
Schmeider, B. (Observatoire de Paris France)
Date Acquired
September 5, 2013
Publication Date
December 1, 1986
Publication Information
Publication: Energetic Phenomena on the Sun: The Solar Maximum Mission Flare Workshop. Proceedings
Subject Category
Solar Physics
Accession Number
87N19330
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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