Statistical investigation of the kinematic and thermal properties of supra-arcade downflows observed during a solar flare

Supra-arcade downflows (SADs) are dark structures descending towards post-reconnection flare loops observed in extreme ultraviolet or X-ray observations and closely related to magnetic reconnection during solar flares. Due the lack of statistical study on SADs a single flare, evolutions kinematic thermal properties process still remain obscure. In this work, we identified 81 that occurred 2013 May 22 using Atmospheric Imaging Assembly (AIA) Solar Dynamics Observatory (SDO). The each SAD, including appearance time, height, projective velocity, acceleration were recorded. We found heights become larger which is likely due lift bottom plasma sheet. decay phase, region where mainly appear moves from north part south side possibly secondary eruption side. trajectories most can be fitted by one two deceleration processes, while some special ones have positive accelerations descent. For properties, selected 54 SADs, whose front body could clearly distinguished surrounding entire descent, perform Differential Emission Measure analysis. It revealed temperatures SAD tend increase their downward courses, relationship between density temperature indicates heating caused adiabatic compression.