Slipping Magnetic Reconnection of Flux Rope Structures as a Precursor to an Eruptive X-class Solar Flare |
|
Ting Li Submitted: 2016-08-08 21:02
We present the quasi-periodic slipping motion of flux rope
structures prior to the onset of an eruptive X-class flare on 2015
March 11, obtained by the Interface Region Imaging
Spectrograph (IRIS) and the Solar Dynamics
Observatory (SDO). The slipping motion occurred at the north
part of the flux rope and seemed to successively peel off the flux
rope. The speed of the slippage was 30-40 km s-1, with an
average period of 130±30 s. The Si IV 1402.77 Å line
showed a redshift of 10-30 km s-1 and a line width of
50-120 km s-1 at the west legs of slipping structures,
indicative of reconnection downflow. The slipping motion lasted
about 40 min and the flux rope started to rise up slowly at the late
stage of the slippage. Then an X2.1 flare was initiated and the flux
rope was impulsively accelerated. One of the flare ribbons swept
across a negative-polarity sunspot and the penumbral segments of the
sunspot decayed rapidly after the flare. We studied the magnetic
topology at the flaring region and the results showed the existence
of a twisted flux rope, together with quasi-separatrix layers (QSLs)
structures binding the flux rope. Our observations imply that
quasi-periodic slipping magnetic reconnection occurs along the
flux-rope-related QSLs in the preflare stage, which drives the later
eruption of the flux rope and the associated flare.
Authors: Ting Li, Kai Yang, Yijun Hou & Jun Zhang
Projects: IRIS
|
Publication Status: accepted for publication in ApJ
Last Modified: 2016-08-10 16:05
|
 
 
 
 
|
|