TY  - JOUR
A1  - Green, Lucie M.
A1  - Kliem, Bernhard
T1  - Flux rope formation preceding coronal mass ejection onset
N2  - We analyze the evolution of a sigmoidal (S-shaped) active region toward eruption, which includes a coronal mass ejection (CME) but leaves part of the filament in place. The X-ray sigmoid is found to trace out three different magnetic topologies in succession: a highly sheared arcade of coronal loops in its long-lived phase, a bald-patch separatrix surface (BPSS) in the hours before the CME, and the first flare loops in its major transient intensity enhancement. The coronal evolution is driven by photospheric changes which involve the convergence and cancellation of flux elements under the sigmoid and filament. The data yield unambiguous evidence for the existence of a BPSS, and hence a flux rope, in the corona prior to the onset of the CME.
Y1  - 2009
UR  - https://publishup.uni-potsdam.de/frontdoor/index/index/docId/31676
UR  - http://iopscience.iop.org/2041-8205
SN  - 2041-8213
ER  -