Onset of phase slip in superflow through channels

Publisher Website
Google Scholar
Abstract
The energy required to change an initially uniform-flow field in a channel to a field containing a vortex is evaluated. It is found that this includes an energy impulse propagated in from the two ends of the channel. The result can be used to define the free energy of the vortex in an entirely unambiguous manner, permitting one to determine the amount of energy dissipated from the superfliud velocity field during an arbitrary phase-slip process. For the special case of a circular vortex ring propagating upstream, the free energy is found to have precisely the form assumed in current theories of intrinsic critical velocities. Further possible applications of the present more general result are discussed.