Third sound interaction with pinned vortices in He-4 superfluid films

Superfluid circulation states are modified by high-amplitude third sound re sonances and remain as persistent currents after the sound is removed. They are the result of pinned vortices at areal densities at on the order of te ns of thousands per square centimeter interacting with the wave. A model fo r the flow-assisted, thermal activation of vortices has successfully reprod uced both the temperature and amplitude dependence of the swirling. (C) 200 0 Elsevier Science B.V. All rights reserved.