Bubble nucleation in a superfluid He3–He4 mixture induced by acoustic wave

Abstract

The nucleation dynamics of bubbles induced by an acoustic wave pulse in He3–He4 liquid mixtures is reported. The experiment is performed mixtures with fixed He3 concentrations of about 4% and 25% and for pure superfluid He4. When a pulse of 1ms duration is applied to the mixture at the saturated vapor pressure, a spherical bubble is nucleated on the active area of a piezoelectric transducer. For the case of pure He4 it is not a spherically shaped bubble but an irregularly shaped, larger one that is observed. Pictures of the bubble expansion and contraction motions after the nucleation are taken with a high speed CCD camera. The temperature dependence of the bubble nucleation is also investigated by changing the acoustic wave power. The results show that the nucleation and growth dynamics of a cavitation bubble depend greatly on the He3 concentration and temperature.