On the interaction of second sound shock waves and vorticity in superfluid helium

Abstract

Two second sound shock waves were propagated successively into initially quiescent superfluid helium. With long separation times the waveforms are identical, but with shorter times the flow behind the second shock decays anomalously, revealing the presence of fluid disturbances produced near the heater by the first pulse. In order to study the vortical nature of these disturbances, second sound shocks were produced in rotating superfluid helium. Propagation of shocks both along and normal to the axis of rotation was studied, the former case proving to be similar to the experiment with successive shocks.