Photospheric shear flows along the magnetic neutral line of Active Region 10486 prior to an X10 flare

Guo Yang, Yan Xu, Wenda Cao, Haimin Wang, Carsten Denker, Thomas R. Rimmele

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53 Scopus citations


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 0″14 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.

Original languageEnglish (US)
Pages (from-to)L151-L154
JournalAstrophysical Journal
Issue number2 II
StatePublished - Dec 20 2004

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


  • Sun: activity
  • Sun: atmospheric motions
  • Sun: flares
  • Sun: photosphere
  • Sunspots
  • Techniques: high angular resolution


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