Modified Hydrodynamic Theory of Sonoluminescence.

Since the first observations of sonoluminescence, researchers have studied it to determine the mechanisms responsible for its existence. Many theories have been offered as possible explanations for sonoluminescence, but only two of these theories gained widespread acceptance. Nevertheless, there are still aspects of sonoluminescence that are unexplained. Temperature deviations and mechanical deviations exist that are not completely explained by any of the theories to date. One explanation is the formulation of plasma inside the cavitation bubble caused by thermal ionization of the contents. A plasma is formed as the temperature rises due the bubble collapse. The ionization process removes energy from the system. However, other processes dominate the system energy before ionization. One of these processes is thermal dissociation. Thermal dissociation of water molecules drains energy from the system that resulted from the adiabatic collapse of the bubble. This transfer of energy causes a noticeable change in the response of the mechanical system as well as in the expected temperature. This process, in turn, provides the free radicals necessary for sonoluminescence.