OPTIMIZATION OF THE CAVITATION ACTIVITY IN PULSED ULTRASOUND FIELDS

In the given work an attempt was made to develop an approach for optimization the conditions of insonation in pulsed ultrasound fields. Cavitation activity was estimated by the sonoluminescence (SL) intensity. The hydrodphone output placed behind the focal spot of a radiator was registered simultaneously with the photomultiplier output. It has been shown that with increase in intensity of ultrasound the maximum of SL intensity is shifted aside longer pulse periods and shorter pulse durations. From the results received it is possible to allocate two thresholds of multibubble cavitation while increasing pulse duration or decreasing pulse period: the first corresponds to the occurrence of light pulses, and the second- to the step-like increase of the SL intensity. The second threshold of cavitation is characterized by the sharp increase of the absorption of ultrasound in cavitation zone. The reason of this increase is evidently connected with the increase in volumetric bubbles in cavitation zone