Experimental study of transient paths to the extinction in sonoluminescence

RAÚL URTEAGA; DAMIÁN H. DELLAVALE; GABRIELA F. PUENTE; FABIÁN J. BONETTO

JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA

Año: 2008 vol. 124 p. 1490 - 1496

0001-4966

An experimental study of the extinction threshold of single bubble sonoluminescence in an air-watersystem is presented. Different runs from 5% to 100% of air concentrations were performed at roompressure and temperature. The intensity of sonoluminescence (SL) and time of collapse (tc) withrespect to the driving were measured while the acoustic pressure was linearly increased from theonset of SL until the bubble extinction. The experimental data were compared with theoreticalpredictions for shape and position instability thresholds. It was found that the extinction of thebubble is determined by different mechanisms depending on the air concentration. Forconcentrations greater than  30%–40% with respect to the saturation, the parametric instabilitylimits the maximum value of R0 that can be reached. On the other hand, for lower concentrations,the extinction appears as a limitation in the time of collapse. Two different mechanisms emerge inthis range, i.e., the Bjerknes force and the Rayleigh–Taylor instability. The bubble acoustic emissionproduces backreaction on the bubble itself. This effect occurs in both mechanisms and is essentialfor the correct prediction of the extinction threshold in the case of low air dissolvedconcentration.