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

TL;DR

This study documents how a rotating sunspot in active region 08858 led to the formation and eruption of an inverse S-shaped filament, accompanied by a flare and CME, highlighting the role of sunspot rotation in filament dynamics.

Contribution

It provides detailed observational evidence linking sunspot rotation to filament formation and eruption, emphasizing the importance of rotation in solar eruptive activities.

Findings

Sunspot rotation reached up to 20 degrees per hour.

Filament formation was associated with rapid sunspot rotation and magnetic flux increase.

Filament eruption coincided with a C-class flare and CME.

Abstract

We find that a sunspot with positive polarity had an obvious counter-clockwise rotation and resulted in the formation and eruption of an inverse S-shaped filament in NOAA active region (AR) 08858 from 2000 February 9 to 10. The sunspot had two umbrae which rotated around each other by 195 degrees within about twenty-four hours. The average rotation rate was nearly 8 degrees per hour. The fastest rotation in the photosphere took place during 14:00UT to 22:01UT on February 9, with the rotation rate of nearly 16 degrees per hour. The fastest rotation in the chromosphere and the corona took place during 15:28UT to 19:00UT on February 9, with the rotation rate of nearly 20 degrees per hour. Interestingly, the rapid increase of the positive magnetic flux just occurred during the fastest rotation of the rotating sunspot, the bright loop-shaped structure and the filament. During the sunspot rotation, the inverse S-shaped filament gradually formed in the EUV filament channel. The filament experienced two eruptions. In the first eruption, the filament rose quickly and then the filament loops carrying the cool and the hot material were seen to spiral into the sunspot counterclockwise. About ten minutes later, the filament became active and finally erupted. The filament eruption was accompanied with a C-class flare and a halo coronal mass ejection (CME). These results provide evidence that sunspot rotation plays an important role in the formation and eruption of the sigmoidal active-region filament.