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On the Dynamics of Small-Scale Solar Magnetic ElementsWe report on the dynamics of the small-scale solar magnetic field, based on analysis of very high resolution images of the solar photosphere obtained at the Swedish Vacuum Solar Telescope. The data sets are movies from 1 to 4 hr in length, taken in several wavelength bands with a typical time between frames of 20 s. The primary method of tracking small-scale magnetic elements is with very high contrast images of photospheric bright points, taken through a 12 A bandpass filter centered at 4305 A in the Fraunhofer 'G band.' Previous studies have established that such bright points are unambiguously associated with sites of small-scale magnetic flux in the photosphere, although the details of the mechanism responsible for the brightening of the flux elements remain uncertain. The G band bright points move in the intergranular lanes at speeds from 0.5 to 5 km/s. The motions appear to be constrained to the intergranular lanes and are primarily driven by the evolution of the local granular convection flow field. Continual fragmentation and merging of flux is the fundamental evolutionary mode of small-scale magnetic structures in the solar photosphere. Rotation and folding of chains or groups of bright points are also observed. The timescale for magnetic flux evolution in active region plage is on the order of the correlation time of granulation (typically 6-8 minutes), but significant morphological changes can occur on timescales as short as 100 S. Smaller fragments are occasionally seen to fade beyond observable contrast. The concept of a stable, isolated subarcsecond magnetic 'flux tube' in the solar photosphere is inconsistent with the observations presented here.
Document ID
19970026470
Acquisition Source
Marshall Space Flight Center
Document Type
Reprint (Version printed in journal)
External Source(s)
doi:10.1086/177250
Authors
Berger, T. E. (Stanford Univ. Stanford, CA United States)
Title, A. M. (Lockheed Martin Corp. Palo Alto, CA United States)
Date Acquired
September 6, 2013
Publication Date
May 20, 1996
Publication Information
Publication: The Astrophysical Journal
Publisher: American Astronomical Society
Issue: 463
Subject Category
Solar Physics
Report/Patent Number
NAS 1.26:204729
NASA-CR-204729
Accession Number
97N25743
Funding Number(s)
CONTRACT_GRANT: NAS8-39747
CONTRACT_GRANT: NAS5-30386
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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