Formation of Post-CME Blobs Observed by LASCO-C2 and K-Cor on 2017 September 10

Abstract

Abstract Understanding the formation of post-CME blobs, we investigate 2 blobs in the outer corona observed by LASCO-C2 and 34 blobs in the inner corona by K-Cor on 2017 September 10 from 17:11 to 18:58 UT. By visual inspection of the structure of a post-CME current sheet (CS) and its associated blobs, we find that the CS is well identified in the K-Cor and its radial lengths are nine times longer than lateral widths, indicating the CS is unstable to the linear tearing mode. The inner corona blobs can be classified into two groups: 27 blobs generated in the middle of the CS (Group 1) and 7 blobs occurred above the tips of it (Group 2). Their lateral widths are and , which is smaller than, or similar to, those of the CS. They have elongated shapes: ratios of lateral to radial widths are and , respectively. In the first group, only three blobs propagate above the tip of the CS while the others are located in the CS. In the second group, only two blobs have associations with those of outer corona in their temporal and spatial relationship and their initial heights are 1.81 and 1.95 R ☉, measured from the center of the Sun. The others cannot be identified in the outer corona. Our results first demonstrate that LASCO-C2 blobs could be generated by the tearing mode instability near the tips of post-CME CSs, similar to the magnetic reconnection process in the tail CS of Earth's magnetosphere.