Plasma Flows Observed in Magnetic Flux Concentrations and Sunspot Fine Structure Using Adaptive Optics

We present diffraction-limited observations of magnetic flux concentrations and penumbral and umbral fine structure within an active region observed at disk center. We recorded G-band images, magnetograms, Dopplergrams, and narrowband filtergrams, using the Universal Birefringent Filter (UBF) at the Dunn Solar Telescope (DST). The National Solar Observatory (NSO) adaptive optics system at the DST was used to achieve diffraction-limited long-exposure imaging with a high signal-to-noise ratio. The main results can be summarized as follows: Strong and spatially narrow downflows are observed at the edge of magnetic structures, such as small flux concentrations (sometimes also referred to as flux tubes), pores, a light bridge, and the sunspot umbrae. For the particular sunspot observed, we find strong evidence for what appear to be vigorous, small-scale convection patterns in a light bridge. We observe extremely narrow (<02) channels or sheets of downflowing plasma. Flux concentrations as seen in intensity expand from a height close to where the continuum is formed to the height of formation for the G band. These observations indicate that the G band forms in the mid-photosphere. We are able to identify individual penumbral fibrils in our data and find a bright (hot) upflow and a more vertical field structure at the filament footpoint near the umbral boundary. The observations are consistent with a filament geometry in which the field and flow turn to a nearly horizontal, dark structure over a distance of about 02. In the deep photosphere we observe strong upflows of the order of 1 km s^-1 in umbral dots. We compare our results with theoretical model predictions.