Shape and extinction thresholds in sonoluminescence parameter space

Experimental single bubble sonoluminescence (SBSL) ambient radius, acoustic drive pressure (R-o-P-a) phase diagrams are compared with predictions of t he Dissociation Hypothesis (DH) and calculations of the n = 2, 3, 4 shape t hresholds, focusing on the location of unstable SBSL and the extinction thr eshold. A phase diagram for experimental runs with a 20% air saturation is shown to indicate the location of the SBSL extinction threshold. Mixtures w ith appropriate concentrations of argon and nitrogen are presented to show the location of unstable SBSL. The results are consistent with the DH and s how that unstable SBSL and the extinction threshold appear to coincide more closely with the n = 4 shape threshold. (C) 2000 Acoustical Society of Ame rica.