Eruptions of two flux ropes observed by SDO and STEREO

Abstract

Aims. We report for the first time the hot and cool components of two flux ropes simultaneously observed by SDO and STEREO, and the relationship between the flux rope eruptions and the coronal mass ejection (CME). Methods. Employing SDO and STEREO A and B observations, we investigated the eruptive event of two flux ropes and their associated activities in active region (AR) 11402 on January 23, 2012. Results. In SDO/AIA 94 Å (∼6.4 MK) and 131 Å (∼10 MK) images, a twisted flux rope appeared from 00:44 UT, which was located in AR 11402. Another longer saddle-shaped flux rope, with twisted fine structures, appeared 25 min later. This was located across the two ARs 11401 and 11402. These two flux ropes initially rose rapidly, then slowly, and finally were again accelerated fast. The two flux ropes are also identified in the STEREO A and B 195 Å (∼1.4 MK), 304 Å (0.06-0.08 MK), 284 Å (∼1.8 MK), and 171 Å (∼1.0 MK) observations. We suggest that the flux ropes may have both hot and cool components. Investigating the flux rope eruptions with their associated CME, we find that the erupting flux ropes are co-spatial with the CME bright core and the expanding overlying flux loops with the CME bright front. © 2013 ESO.