INFLUENCE OF THE SOUND FIELD ON THE INTENSITY OF SONOLUMINESCENCE

Cavitation-field sonoluminescence intensity was measured in correlatio n with sound pressure and its harmonic and subharmonic component signa ls generated from a well-defined cavitation field in a distilled-water filled rectangular cell by changing the acoustic frequency and the vo ltage applied to the transducer. Optics was designed to ensure that al l the sonoluminescing positions in the cell were delectable by a photo multiplier tube. The results show that it is the second harmonic compo nent of the sound pressure waveform, rather than the subharmonic one, which gives a reliable indication of the threshold of the cavitation a nd the onset of the cavitation-field sonoluminescence. The sonolumines cence signal exhibits a linear relationship with the simultaneously me asured second harmonic component signal and is likely to originate mai nly from the subset of stable cavitation bubbles in the cavitation fie ld.