  We observe the motion of cool and hot plasma in a multi-stranded post flare
loop system that evolved in the decay phase of a two ribbon M1.0 class flare in
AR 11093 on 7 August 2010 using SDO/AIA 304 \AA\ and 171 \AA\ filters. The
moving intensity feature and its reflected counterpart are observed in the loop
system at multi-temperature. The observed hot counterpart of the plasma that
probably envelopes the cool confined plasma, moves comparatively faster
($\sim$34 km s$^{-1}$) to the later (29 km s$^{-1}$) in form of the spreaded
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 post flare loop
system through impulsive flare heating processes. Complementing our
observations of moving multi-temperature intensity features in the post flare
loop 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.
