The possible trigger mechanism of the solar eruption in 2012 July 12
Thursday, 18 December 2014
We examine flare eruptions (X1.4) on 2012 July 7 in the NOAA active region 11520. Using an advanced non-linear force-free field (NLFFF) extrapolation method based on the SDO/HMI vector magnetograms, we investigate the evolution of the magnetic field during the eruption. Also, based on the extrapolated field we determine the rough positions of the separatrix surface, where might be the magnetic reconnection site in this active region. Moreover, compared with EUV images, the nullpoint position has good alignment with the EUV bright point. In addition, the sunspot rotation may lead the magnetic reconnection.