Inhomogeneous pressure field inside a collapsing bubble accelerated by an acoustic pulse.
The temperature inside a collapsing bubble could become very high if a converging shock wave were launched inside the bubble. Even if the collapse speed reaches Mach 4, the recent models and experiments show that this shock wave is not necessary to explain the sonoluminescence. Its hypothetical existence depends strongly on the assumption made in the various numerical models proposed. However, it has been established that its generation depends strongly on the acceleration of the bubble surface. This work presents an experimental parametric study demonstrating that a pressure pulse applied on the bubble with an accurate timing significantly accelerates the bubble collapse. It is shown that the induced brightness gain is very sensitive to the time of arrival of the pulse. Moreover, a numerical simulation of these experiments relates this dependence to the gas dynamic in the bubble.
Laboratoire des Milieux Désordonnés et Hétérogènes, Université de Paris 06, UMR Centre Nationale de la Recherche Scientifique 7603, 4 place Jussieu,75252 Paris Cedex 05, France. thomasjl@ccr.jussieu.fr
Jean-Louis
JL
Thomas