On the mechanism of multi-bubble sonoluminescence

The thermal chemiluminescent model of multibubble sonoluminescence (MBSL) is considered, and the contradictions that follow from its basic propositions are analyzed. It is shown that, if the thermal mechanism of sonoluminescence (SL) is operative, the continuous spectrum should be emitted before the band spectrum. It is established that, if the thermal recombination mechanism of a solid is operative, the duration of SL should be at least two orders of magnitude longer than that observed experimentally (<5 ns); according to the chemiluminescent model of SL, the SL burst time must be several orders of magnitude longer. Consideration is given to the previously proposed mechanism of emission of spectral lines of metals from solutions of alkali and alkaline-earth metal salts, which correlates with results of sonolysis of salt solutions under the action of ultrasound (US) pulses. A mechanism based on the theory of local electrification of cavitation bubbles in the US field is put forward to treat MBSL. It is shown that this mechanism agrees with experimental results: the SL burst time corresponds to the characteristic time of fluorescence.