Abstract:
We observe the motion of cool and hot plasma in a multi-stranded post-flare loop (PFL) system that evolved in the decay phase of a two-ribbon M1.0 class flare inAR 11093 on 2010 August 7 using the Solar DynamicsObservatory/Atmospheric Imaging Assembly 304 Å and 171Å filters. The moving intensity feature and its reflected counterpart are observed in the loop system at multiple temperatures. The observed hot counterpart of the plasma probably envelopes the cool confined plasma and moves comparatively faster (∼34 km s−1) than the latter (29 km s−1) in the form of a spreading intensity feature. The propagating plasma and intensity reflect from the region of another footpoint of the loop. The subsonic speed of the moving plasma and associated intensity feature may be most likely evolved in the PFL system through impulsive flare heating processes. Complementing our observations of moving multi-temperature intensity features in the PFL system and its reflection, we also attempt to solve two-dimensional ideal magnetohydrodynamic equations numerically using the VAL-IIIC atmosphere as an initial condition to simulate the observed plasma dynamics. We consider a localized thermal pulse impulsively generated near one footpoint of the loop system during the flare processes, which is launched along the magnetic field lines at the solar chromosphere. The pulse steepens into a slow shock at higher altitudes while moving along this loop system, which triggers plasma perturbations that closely exhibit the observed plasma dynamics.
