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Observations of photospheric magnetic fields and shear flows in flaring active regionsHorizontal flows in the photosphere and subsurface convection zone move the footpoints of coronal magnetic field lines. Magnetic energy to power flares can be stored in the corona if the flows drive the fields far from the potential configuration. Videodisk movies were shown with 0.5 to 1 arcsecond resolution of the following simultaneous observations: green continuum, longitudinal magnetogram, Fe I 5576 A line center (mid-photosphere), H alpha wings, and H alpha line center. The movies show a 90 x 90 arcsecond field of view of an active region at S29, W11. When viewed at speeds of a few thousand times real-time, the photospheric movies clearly show the active region fields being distorted by a remarkable combination of systematic flows and small eruptions of new flux. Magnetic bipoles are emerging over a large area, and the polarities are systematically flowing apart. The horizontal flows were mapped in detail from the continuum movies, and these may be used to predict the future evolution of the region. The horizontal flows are not discernable in H alpha. The H alpha movies strongly suggest reconnection processes in the fibrils joining opposite polarities. When viewed in combination with the magnetic movies, the cause for this evolution is apparent: opposite polarity fields collide and partially cancel, and the fibrils reconnect above the surface. This type of reconnection, driven by subphotospheric flows, complicates the chromospheric and coronal fields, causing visible braiding and twisting of the fibrils. Some of the transient emission events in the fibrils and adjacent plage may also be related.
Document ID
19890006486
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Tarbell, T. (Lockheed Missiles and Space Co. Palo Alto, CA, United States)
Ferguson, S. (Lockheed Missiles and Space Co. Palo Alto, CA, United States)
Frank, Z. (Lockheed Missiles and Space Co. Palo Alto, CA, United States)
Title, A. (Lockheed Missiles and Space Co. Palo Alto, CA, United States)
Topka, K. (Lockheed Missiles and Space Co. Palo Alto, CA, United States)
Date Acquired
September 5, 2013
Publication Date
November 1, 1988
Publication Information
Publication: NASA, Goddard Space Flight Center, Max 1991: Flare Research at the Next Solar Maximum. Workshop 1: Scientific Objectives
Subject Category
Solar Physics
Accession Number
89N15857
Funding Number(s)
CONTRACT_GRANT: NAS5-26813
CONTRACT_GRANT: NAS8-32805
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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