Modelling single-bubble sonoluminescence with chemical reactions and Coulomb interactions∗

A refined hydro-chemical model was applied to numerical simulation of single-bubble sonoluminescence (SBSL) by taking into account the processes of water vapor evaporation and condensation, heat and mass diffusion, and chemical reactions. The numerical results show significant water vapor dissociations but rather low degrees of ionization. A widely accepted weakly ionized gas model is then used to compute the light emission. Contrary to earlier predictions without chemical reactions, the calculated light spectra and pulses are generally too small to fit to experimental data within stable SBSL range. To alleviate this contradiction, the electrostatic interactions of the ionized gas particles are taken into account, which are shown to lower the ionization potentials of gas species in the bubble significantly, hence resulting in dramatic increase of ion populations. Key words: single-bubble sonoluminescence; Coulomb interactions; lowering of ionization po-tential.