Multibubble sonoluminescence intensity dependence on liquid temperature at different ultrasound intensities.

It is shown that the influence of liquid temperature on the sonoluminescence (SL) intensity is different depending on the ultrasound intensity. At the ultrasound intensities not much higher than the cavitation appearance threshold the SL intensity increases with the temperature. At the ultrasound intensities considerably exceeding the cavitation threshold the SL intensity decreases with an increase of the temperature. At intermediate ultrasound intensities the SL intensity temperature dependence is extreme: the cavitation activity at first increases with temperature, reaches a maximum and then decreases. Continuous and pulsed modes of irradiation at frequencies 880 and 21.9 kHz were used in experiments.