Acoustic emission of subharmonic 1/2 and light emission from NaCl-water solutions were studied by means of the pulsed ultrasound technique for different concentrations. The experimental results, concerning sound and light emission thresholds are presented and discussed to search possible explanatory mechanisms for the observed dependence on salt concentration.

Investigations have been performed on various methods of increasing cavitation activity measured by the intensity of sonoluminescence. It is shown that the effect of the combined action of (a) pulsed modulation of an acoustic field, (b) liquid degassing and cooling and (c) increasing the static pressure considerably exceeds the sum of the effects achieved by each of these methods individually. A more than 250-fold increase of the sonoluminescence intensity has been attained compared with continuous irradiation under normal conditions (room temperature, atmospheric pressure, gas-saturated liquid). An interpretation of the results obtained is proposed.