INVESTIGATING TWO SUCCESSIVE FLUX ROPE ERUPTIONS IN A SOLAR ACTIVE REGION

Journal Article · Sat Jun 01 04:00:00 EDT 2013 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/769/2/L25· OSTI ID:22364152

Cheng, X.; Zhang, J.; Ding, M. D.; Guo, Y. ^[1]; Olmedo, O. ^[2]; Sun, X. D. ^[3]

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1. School of Astronomy and Space Science, Nanjing University, Nanjing 210093 (China)
2. NRC, Naval Research Laboratory, Washington, DC 20375 (United States)
3. W. W. Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305 (United States)

We investigate two successive flux rope (FR1 and FR2) eruptions resulting in two coronal mass ejections (CMEs) on 2012 January 23. Both flux ropes (FRs) appeared as an EUV channel structure in the images of high temperature passbands of the Atmospheric Imaging Assembly prior to the CME eruption. Through fitting their height evolution with a function consisting of linear and exponential components, we determine the onset time of the FR impulsive acceleration with high temporal accuracy for the first time. Using this onset time, we divide the evolution of the FRs in the low corona into two phases: a slow rise phase and an impulsive acceleration phase. In the slow rise phase of FR1, the appearance of sporadic EUV and UV brightening and the strong shearing along the polarity inverse line indicates that the quasi-separatrix-layer reconnection likely initiates the slow rise. On the other hand, for FR2, we mainly contribute its slow rise to the FR1 eruption, which partially opened the overlying field and thus decreased the magnetic restriction. At the onset of the impulsive acceleration phase, FR1 (FR2) reaches the critical height of 84.4 ± 11.2 Mm (86.2 ± 13.0 Mm) where the decline of the overlying field with height is fast enough to trigger the torus instability. After a very short interval (∼2 minutes), the flare emission began to enhance. These results reveal the compound activity involving multiple magnetic FRs and further suggest that the ideal torus instability probably plays the essential role of initiating the impulsive acceleration of CMEs.

• OSTI ID: 22364152
• Journal Information: Astrophysical Journal Letters, Journal Name: Astrophysical Journal Letters Journal Issue: 2 Vol. 769; ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ACCELERATION
ACCURACY
ASTRONOMY
ASTROPHYSICS
ERUPTION
EXTREME ULTRAVIOLET RADIATION
IMAGES
LAYERS
MAGNETIC RECONNECTION
MASS
PLASMA INSTABILITY
SHEAR
SOLAR CORONA
SOLAR FLARES
SUN
TOPOLOGY