Vinen’s Energy Barrier

In 1963, the late W. F. (“Joe”) Vinen concluded, partly on intuitive grounds, that the ab initio creation of a quantized vortex line in superfluid 4He is impeded by an energy barrier. We place this prescient insight into context and review subsequent theoretical and experimental research that calculated the height of the barrier and validated the result through measurements on negative ions moving through superfluid 4He above the Landau critical velocity. We discuss the implications of these results for other superfluids, including laser-cooled dilute atomic gases, and for the subsequent development of superfluid hydrodynamics.