Experimental study of Extinction Mechanisms in Sonoluminescence

R. URTEAGA, D. DELLAVALE, G. F. PUENTE, F.J. BONETTO

JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA

American Institute of Physics

Lugar: Mellville, New York; Año: 2008 p. 1 - 2

0001-4966

An experimental study of the extinction threshold of single bubble sonoluminescence in an air-water system is presented. Different runs from 5% to 100% of air concentrations were performed at room pressure and temperature. The intensity of sonoluminescence SL[1] and time of collapse tc[1] with respect to the driving were measured while the acoustic pressure was linearly increased from the onset of SL until the bubble extinction. The experimental data were compared with theoretical predictions for shape and position instability thresholds. We found that the extinction of the bubble is determined by different mechanisms depending on the air concentration. For concentrations greater than 30%–40% with respect to the saturation, the parametric instability limits 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 in this range, i.e., the Bjerknes force and the Rayleigh–Taylor instability. The bubble acoustic emission produces backreaction on the bubble itself. This effect occurs in both mechanisms and is essential for the correct prediction of the extinction threshold in the case of low air dissolved concentration.