Large-scale flows in prominence cavities

Regions of rarefied density often form cavities above quiescent prominences. We observed two different cavities with the Coronal Multichannel Polarimeter on 2005 April 21 and with Hinode/EIS on 2008 November8. Inside both of these cavities, we find coherent velocity structures based on spectral Doppler shifts. These flows have speeds of 5-10 km s^-1, occur over length scales of tens of megameters, and persist for at least 1hr. Flows in cavities are an example of the nonstatic nature of quiescent structures in the solar atmosphere.