  Sunward-flowing voids above post-coronal mass ejection (CME) flare arcades
were first discovered using the soft X-ray telescope (SXT) aboard Yohkoh and
have since been observed with TRACE (extreme ultra-violet (EUV)), SOHO/LASCO
(white light), SOHO/SUMER (EUV spectra), and Hinode/XRT (soft X-rays (SXR)).
Supra-arcade downflow (SAD) observations suggest that they are the
cross-sections of thin flux tubes retracting from a reconnection site high in
the corona. Supra-arcade downflowing loops (SADLs) have also been observed
under similar circumstances and are theorized to be SADs viewed from a
perpendicular angle. Previous studies have presented detailed SAD observations
for a small number of flares. In this paper we present a substantial SADs and
SADLs flare catalog. We have applied semi-automatic detection software to
several of these events to detect and track individual downflows thereby
providing statistically significant samples of parameters such as velocity,
acceleration, area, magnetic flux, shrinkage energy, and reconnection rate. We
discuss these measurements, how they were obtained, and potential impact on
reconnection models.
