AN ASPECT OF SONOLUMINESCENCE FROM HYDRODYNAMIC THEORY

Sonoluminescence (SL), the phenomenon of light emission associated with the collapse of bubble oscillating under ultrasonic pressure field has been studied by solving the conservation equations for the gas inside bubble analytically. Heat transfer in the liquid layer adjacent to the bubble wall has also been considered in this analysis. It has been found that the gas behavior is neither adiabatic nor isothermal for a bubble under ultrasound conditions. In this analysis, the launch condition and the Hugoniot curve for the shock propagation have been identified, and the shock duration of 2.7 to 17 ps, which is comparable to experimental result, has been obtained with the use of a similarity solution for converging spherical shock. For SL, the gas temperature after the shock focusing has been found to be 7000 K similar to 44000 K, depending on the equilibrium bubble radius and the driving amplitude of ultrasound. It has also been found that the heat flux at bubble collapse is as large as 47 GW/m(2), which could be more than enough to cause an explosion of an explosive crystal.