ON THE MECHANISM OF RELAXATION OSCILLATION IN SONOLUMINESCENCE

The mechanism generating relaxation oscillation in sonoluminescence is experimentally investigated. After the ranges of temperature and pres sure amplitude within which the phenomenon occurs are examined, the ch ange in temperature and driving voltage of the transducer accompanying the phenomenon is observed to insure that one of the causes of disapp earance of radiating conditions is the temperature rise in the liquid during sonoluminescence. We also note that the gas content in the liqu id varies according to the radiating and vanishing periods, observed i n gaseous cavitation and vapor cavitation at the radiating and vanishi ng periods, respectively. By measuring the oxygen content, the relatio n between these two cavitation states and the gas content in the liqui d is investigated to confirm that one of the main reasons for the tran sition from the radiating state to vanishing state, and of the reverse transition, is the gas content in the liquid. Furthermore, the repeti tion mechanism of radiation and evanescence is experimentally investig ated. (C) 1998 Scripta Technica.