  The 2011 January 28 M1.4 flare exhibits two side-by-side candle-flame-shaped
flare loop systems underneath a larger cusp-shaped structure during the decay
phase, as observed at the northwestern solar limb by the Solar Dynamics
Observatory (SDO). The northern loop system brightens following the initiation
of the flare within the southern loop system, but all three cusp-shaped
structures are characterized by ~ 10 MK temperatures, hotter than the
arch-shaped loops underneath. The "Ahead" satellite of the Solar Terrestrial
Relations Observatory (STEREO) provides a top view, in which the post-flare
loops brighten sequentially, with one end fixed while the other apparently
slipping eastward. By performing stereoscopic reconstruction of the post-flare
loops in EUV and mapping out magnetic connectivities, we found that the
footpoints of the post-flare loops are slipping along the footprint of a
hyperbolic flux tube (HFT) separating the two loop systems, and that the
reconstructed loops share similarity with the magnetic field lines that are
traced starting from the same HFT footprint, where the field lines are
relatively flexible. These results argue strongly in favor of slipping magnetic
reconnection at the HFT. The slipping reconnection was likely triggered by the
flare and manifested as propagative dimmings before the loop slippage is
observed. It may contribute to the late-phase peak in Fe XVI 33.5 nm, which is
even higher than its main-phase counterpart, and may also play a role in the
density and temperature asymmetry observed in the northern loop system through
heat conduction.
