Observations of Plasma Blob Ejection from a Quiescent Prominence by Hinode SOT

We report findings from 0.2" resolution observations of the 2007 October 03 quiescent prominence observed with the Solar Optical Telescope on the Hinode satellite. The observations show clear ejections from the top of the quiescent prominence of plasma blobs. The ejections, originating from the top of rising prominence threads, are impulsively accelerated to Alfvenic velocities and then undergo ballistic motion. The ejections have a characteristic size between ~ 1000 - 2000 km. These characteristics are similar to downwardly propagating knots (typical size ~ 700 km) that have been observed in prominence threads, we suggest that the plasma blob ejections could be the upward moving counterpart to the downwardly propagating knots. We discuss the tearing instability as a possible mechanism to explain the ejections.