Double ejections in the 23 July 2012 SEP event

Recently,it has been proposed that extreme solar Energetic Particle Events (SEPs) are likely caused by twin CMEs. On July 23 2012, a massive eruption led to a large SEP, which is well observed in STEREO-A. Using the 171A and 304A bands of the EUVI imaging from spacecraftSTEREO-A,STEREO-B, and SDO, we report the observations of two coronal mass ejections in the July 23 2012 SEP event. Two ejections were identified with a time separation of ~8 minutes. In the first eruption, a flux rope can be seen with a rotation during the eruption. For the second eruption, there was a deflection of the propagation direction. These features resemble the numerical simulation of a sympathetic eruption investigated by Torok et al (2011). We propose that sympathetic eruptions from complex active regions (AR), as a special subset of the 'twin-CME' scenario, may provide an efficient acceleration site for high energy particles that are observed in large SEPs.