Single-bubble sonoluminescence: shape stability analysis of collapse dynamics in a semianalytical approach

This paper theoretically analyzes the hydrodynamic shape stability problem for sonoluminescing bubbles. We present a semianalytical approach to describe the evolution of shape perturbations in the strongly nonlinear regime of violent collapse. The proposed approximation estimating the damping rate produced by liquid viscosity is used to elucidate the influence of the collapse phase on subsequent evolution of the Rayleigh-Taylor instability. We demonstrate that time derivatives of shape perturbations grow significantly as the bubble radius vanishes, forming the dominant contribution to destabilization during the ensuing bounce phase. By this effect the Rayleigh-Taylor instability can be enhanced drastically, yielding a viable explanation of the upper threshold of driving pressure experimentally observed by Barber et al. [Phys. Rev. Lett. 72, 1380 (1994)].