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We find that a sunspot with positive polarity had an obviouscounter-clockwise rotation and resulted in the formation and eruption of aninverse S-shaped filament in NOAA active region (AR) 08858 from 2000 February 9to 10. The sunspot had two umbrae which rotated around each other by 195degrees within about twenty-four hours. The average rotation rate was nearly 8degrees per hour. The fastest rotation in the photosphere took place during14:00UT to 22:01UT on February 9, with the rotation rate of nearly 16 degreesper hour. The fastest rotation in the chromosphere and the corona took placeduring 15:28UT to 19:00UT on February 9, with the rotation rate of nearly 20degrees per hour. Interestingly, the rapid increase of the positive magneticflux just occurred during the fastest rotation of the rotating sunspot, thebright loop-shaped structure and the filament. During the sunspot rotation, theinverse S-shaped filament gradually formed in the EUV filament channel. Thefilament experienced two eruptions. In the first eruption, the filament rosequickly and then the filament loops carrying the cool and the hot material wereseen to spiral into the sunspot counterclockwise. About ten minutes later, thefilament became active and finally erupted. The filament eruption wasaccompanied with a C-class flare and a halo coronal mass ejection (CME). Theseresults provide evidence that sunspot rotation plays an important role in theformation and eruption of the sigmoidal active-region filament.

Sunspot rotation, filament, and flare: The event on 2000 February 10