Figure 1

The figure shows experimentally achievable sonoluminescing bubbles with a large expansion ratio, which is the maximum radius divided by the ambient radius $R_0$ (i.e., the radius of the bubble immediately after the sound field is turned off). The expansion ratio is independent of which noble gas is used but is dependent on drive level and the concentration of gas in the surrounding water. The largest expansion ratio realized is $30:1$; simulations for this Letter were carried out for a bubble with an ambient radius of 2.2 microns and an expansion ratio of 24. The expansion, collapse, and after bounces are fit by the Rayleigh-Plesset “RP” equation (see discussion in Ref. 2). The radius versus time is not directly experimentally determined for $R<R_0$. For purpose of the simulations, $R(t)$ is extrapolated into this region via the solution to the RP equation.Reuse & Permissions

Figure 2

Density profiles of pure xenon (a) and helium (b) bubbles at an intermediate time between $R_0$ and the minimum radius. This simulation is carried out for the hard-sphere model.Reuse & Permissions

Figure 3

Density profile of helium and xenon inside of a collapsing bubble at four successive moments between $R_0$ and the minimum radius. This calculation was carried out for the hard-sphere model of molecular dynamics.Reuse & Permissions

Figure 4

Maximum temperature vs time (after collapse) near hot spot for hard sphere and VSS MD simulations of various mixtures of helium and xenon inside of a strongly supersonically collapsing piston. The legend shows the percentage of He in the mixture.Reuse & Permissions