Threshold for gas breakdown initiated by an interaction of laser light with aerosol particles

A model constructed previously for plasma production through the laser heating, evaporation, and ionization of a microscopic surface defect is refined in an effort to determine the breakdown conditions in an aerosol. Simple analytic expressions are derived for the threshold laser intensity as a function of the wavelength of the laser light, the dimensions and material of the aerosol particles, the shape of the laser pulse, and the evaporated volume of the particle. The results are compared with experiments on the laser breakdown of air caused by beams from CO₂ and Nd lasers in the presence of an aerosol consisting of carbon particles 0.1–25 μm in radius. The results are also compared with the predictions of the explosion model.