Implosion mechanism for a sonoluminescing gas bubble

Abstract

The shock pulse emanating from a sonoluminescing gas bubble was measured with a needle hydrophone, and the measured data were compared with the analytical results. The magnitude of the shock profile decreases as 1/r, which characterizes spherical shock propagation in a medium. The calculated rise time of the shock pulse is about 5 ns, which is comparable to the measured rise time of 5 similar to 12 us. The pulse signal calculated at 1 mm from the bubble center is about 7.5 atm, which is close to the observed value of 6.5 atm. Below the sonoluminescence threshold of the driving pressure, acoustic emissions were observed with considerably smaller magnitude and longer rise times.