  Solar filaments exhibit a range of eruptive-like dynamic activity, ranging
from the full or partial eruption of the filament mass and surrounding magnetic
structure as a coronal mass ejection (CME), to a fully confined or 'failed'
eruption. On 2011 June 7, a dramatic partial eruption of a filament was
observed by multiple instruments on SDO and STEREO. One of the interesting
aspects of this event is the response of the solar atmosphere as non-escaping
material falls inward under the influence of gravity. The impact sites show
clear evidence of brightening in the observed EUV wavelengths due to energy
release. Two plausible physical mechanisms explaining the brightening are
considered: heating of the plasma due to the kinetic energy of impacting
material compressing the plasma, or reconnection between the magnetic field of
low-lying loops and the field carried by the impacting material. By analyzing
the emission of the brightenings in several SDO/AIA wavelengths, and comparing
the kinetic energy of the impacting material (7.6 x 10^26 - 5.8 x 10^27 ergs)
to the radiative energy (1.9 x 10^25 - 2.5 x 10^26 ergs) we find the dominant
mechanism of energy release involved in the observed brightening is plasma
compression.
