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Session 101 - The Sun.
Display session, Thursday, January 18
North Banquet Hall, Convention Center

[101.04] Motion and Evolution of Solar Magnetic Elements

T. E. Berger (Stanford U.), C. J. Schrijver, R. S. Shine, T. D. Tarbell, A. M. Title (Lockheed-Martin PARL), G. Scharmer (Stockholm Obs., Swedish RAS)

The dynamics of sub-arcsecond solar magnetic flux tubes are analyzed based on very-high resolution movies of photospheric bright points obtained in 1994 at the 50-cm Swedish Solar Vacuum Telescope (SVST) on the island of La Palma, Spain. The bright points are imaged using a 12Å\ bandpass interference filter centered at 4305Å\ in the ``G Band'' molecular bandhead of the CH molecule. The image sets typically consist of up to 4 hours of consecutive images taken at a 10 to 20 second cadence. Spatial resolution throughout the movies averages less than 0\arcsec.5 and many frames in the sets exhibit resolution down to 0\arcsec.25. Magnetic flux elements in the photosphere are shown to move continually along the intergranular lanes at speeds of up to 5 km/sec and ranges up to several thousand km. Evolution of individual magnetic elements is dominated by the local evolution of surrounding granules. Fragmentation and merging is the fundamental mode of evolution of the majority of magnetic elements seen in our data. Rotation and folding of chains or groups of elements is also frequently observed. The time scale for the fragmentation/merging evolution of the elements is on the order of the lifetime of granulation (6--8 minutes), but significant morphological changes are seen to occur on time scales as short as 100 seconds. The concept of a stable, isolated, sub-arcsecond magnetic flux element in the solar photosphere is inconsistent with the observations presented here.

Program listing for Thursday