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We present high-resolution observations of horizontal flow fields measured by local correlation tracking from intensity images in three wavelengths, i.e., G band (GB), white light (WL), and near-infrared (NIR). The observations were obtained on 2003 October 29 within the flaring super active region NOAA 10486, which was the source of several X-class flares, including an X10 flare that occurred near the end of the observing run. The data were obtained at National Solar Observatory/Sacramento Peak (NSO/SP) using the newly developed high-order adaptive optics (AO) system. We also use Dopplergrams and magnetograms from MDI on board SOHO to study the line-of-sight flow and magnetic field. We observe persistent and long-lived (at least 5 hr) strong horizontal and vertical shear flows (both in the order of 1 km s-1) along the magnetic neutral line (NL) until the X10 flare occurred. From lower photospheric level (NIR), the direction of the flows does not change up to the upper photosphere (GB), while the flow speeds in the shear motion regions decrease and, on the contrary, those in regions without shear motions increase with increasing altitude. Right after the X10 flare, the magnetic gradient decreased, while both horizontal and vertical shear flows dramatically enhanced near the flaring NL. Our results suggest that photospheric shear flows and local magnetic shear near the NL can increase after the flare, which may be the result of shear release in the overlying large-scale magnetic system or the reflection of a twisted or sheared flux emergence carrying enough energy from the subphotosphere.

We present high spatial resolution observations of proper motions in the solar NOAA Active Region 10486 using a high-order adaptive optics system, frame selection, and speckle-masking image reconstruction. The data were obtained with the Dunn Solar Telescope of the National Solar Observatory/Sacramento Peak on 2003 October 29. The resolution of the images approaches the diffraction-limited resolution of the Dunn Solar Telescope of about 014 at 527 nm. We analyzed a 2 hr time series with a 1 minute cadence prior to an X10 white-light flare. Local correlation tracking was used to measure the photospheric proper motions. We find specific evidence of strong shear flows along the magnetic neutral line; these shear flows are well defined and correlated with white-light flare kernels in the visible and infrared. The speed along the flow channels can reach up to 1.6 km s-1, and the separation of channels with head-on flows can be less than 1''. Counterstreaming and complex flow patterns have been distinguishing characteristics of this extraordinarily flare-productive active region.

We investigate seismic events, bursts of seismic waves that are generated locally just below the solar surface and that we detect traveling up through the photosphere. We identify a few thousand seismic events by their traveling wave character and —nd that they are associated with continuum darkening and down—ow and have an extent of on average about 10¨15 minutes and 1 Mm. Their birth rate is about 8 ) 10~16 m~2 s ~1. The observed upwardly traveling seismic —ux in the average event (as derived from velocities in the p-mode region of k-u space) is followed after about 3 minutes by some re—ected down- ward —ux. Only a small fraction of the energy generated in the hypocenter of the event below the surface travels straight up for us to see. The bulk of the generated energy is directed or re—ected downward, and is eventually transformed into p-modes. The seismic events at the surface contain about 1.5 ) 1019 Jo f seismic energy each, which corresponds to an average —ux level of about 8.5 kW m~2 over the whole surface. The total energy —ow is likely more than an order of magnitude greater, and is then in the same ballpark as the estimate of Libbrecht for the power required to sustain the p-mode spectrum. We —nd a roughly linear relation between the peak seismic —ux and the peak downward convective velocity associ- ated with each seismic event, which does not —t the highly nonlinear relations found theoretically by Lighthill and Goldreich & Kumar for stochastic excitation by turbulent convection, but does —t the monopole source deduced by Nigam & Kosovichev from a study of the p-mode spectrum. Subject heading: Sun: oscillationsSun: photospherewaves

We report new observations that combine high-precision infrared polarimetry and high-resolution imagery in the visible to demonstrate that most of the quiet solar surface contains a measurable magnetic field. We found that when observed at 1 arcsec2 resolution, 68% of the observed area contains magnetic flux higher than 5×1015 Mx (corresponding to an apparent average field of 1 G). The majority of these magnetic features have magnetic flux below 5×1016 Mx. Their magnetic field strengths range from below 200 to 1000 G, which means that their filling factors are on the order of 1%. The spatial distribution and time evolution of these magnetic features are closely associated with the solar granulation. The properties of these weak granular magnetic features we observed differ from those of the intranetwork fields described in earlier observations. We also observed the formation and disappearance of a kilogauss magnetic feature associated with the development of intergranular lanes, which may be evidence of convective collapse.

We study a time sequence of the velocity field measured in a sunspot light bridge classified as photospheric. The data provide clear evidence for a convective origin of the photospheric light-bridge phenomenon. Furthermore, the data strongly indicate that a form of oscillatory magnetoconvection is the physical process responsible for the formation of the observed light bridge. We observe umbral dots and find in them a very small upward velocity of order 50 m s-1. Both the intensity and the velocity signal vary in time. Some umbral dots fade over a period of about 15-20 minutes and then reappear at the same location. In the particular sunspot observed, umbral dots give the impression of being aligned in lanes that appear to separate individual flux fragments within the umbra.