Measurements of Solar Magnetic Element Dispersal

Abstract

The dispersal of magnetic elements in the solar photospheric flow field is studied by tracking individual ``magnetic bright points'' (MBPs) identified in a G-band 4305 {Å} filtergram time series obtained at the 50 cm Swedish Vacuum Solar Telescope on La Palma, Spain. The time series spans approximately 70 minutes with a field of view of 29" x 29" near disk center. All images in the time series are restored to near the telescope diffraction limit (~0.2" in the G band) using partitioned phase diverse speckle techniques. Regions of enhanced magnetic network and quiet Sun are examined. In the network region, automated tracking of individual MBPs reveals approximately Gaussian diffusion, with indications for slightly ``superdiffusive'' dispersal. The inferred Gaussian diffusion coefficient is 60.4 +/- 10.9 km^2 s^-1. In the quiet-Sun region, local correlation tracking velocity measurements show the dispersal of artificial tracers to be non-Gaussian over most of our data set with indications of an asymptotic approach to a 285 km^2 s^-1 Gaussian diffusion.