Nonequilibrium Plasma Theory of a Cavitation Bubble Containing Xenon Gas

Abstract

The behavior of a single xenon bubble in an adiabatic compression process was investigated theoretically. Rayleigh's equation for the bubble dynamics was coupled with the detailed collisional and radiative processes for xenon plasma to obtain plasma conditions in a bubble. A two-temperature model for electrons and heavy particles was adopted to estimate the luminescence property from a spherical bubble. For the conditions of initial bubble radius of 10 to 150 μm and pressure change of 200 to 800 kPa, the maximum electron temperature ranged from 5000 to 15000 K and electron number densities about 10¹⁷ to 10²⁰ cm^-3 at the minimum bubble radius. The plasma in a bubble was in thermally nonequilibrium state during the compression process, and generally the maximum electron temperature was significantly lower than the heavy particle one. The emission intensity from cavitation bubbles was sensitive to the change rate of pressure and the bubble radius.