Experimental observations of the effect of ambient pressure on single-bubble sonoluminescence

Abstract

The experimental observations of the influence of ambient pressure on single-bubble sonoluminescence will be presented. In the SBSL regime as the ambient pressure was decreased only about 10%, the SL intensity increased significantly as predicted [L. Kondic, C. Yuan, and C. K. Chan, Phys. Rev. E 57(1), R32–R35 (1998)]. There was an increase of about five times in SL intensity as the ambient pressure was decreased by about 10%–12%, at constant driving acoustic pressure. This increment continued until a certain value of the ambient pressure, below which the bubble became unstable and vanished. The equilibrium radius and the maximum radius of the SBSL bubble both incerased with decrease of ambient pressure. This observation provides valuable insight into the mass flow mechanism between the bubble and the liquid, and gives the first direct confirmation of ‘‘argon bubble hypothesis.’’ [Work supported by NSERC and Concordia Seagram Fund for Innovative Research.]