Acoustic modeling of plasma-induced vapor bubbles

Plasma-induced bubbles respond to time-dependent injection of energy which modifies the acoustic output relative to ''classical'' gas bubbles. Additionally, they consist primarily of hot vapor which complicates the thermodynamics, elevates the importance of some traditionally untreated variables, and requires additional physical process treatments beyond the basic hydrodynamics. A code that is based upon fundamental physical principles was developed to study the importance of many of these variables. The code is capable of treating the actual driving circuit, resultant plasma behavior, transition from cylindrical to spherical geometry early in the discharge, radiation production, plasma chemistry, thermal transport, and hydrodynamics in a modified Flynn formulation. Primary output consists of bubble wall acceleration, radius, etc., energy balance, and far field pressure. The code has been validated with experimental data and will be compared with ongoing hydrocode model development as well. Experimental and theoretical results are presented for large vapor bubbles. [Work supported by the U.S. Navy.]