Statistical analysis of spectra of acoustic signals from laser breakdown initiated on monodispersed solid aerosol particles

The results of statistical analysis of the spectra of acoustic signals radiated by local plasma formations initiated on single 400-micrometer SiO2 and 170-micrometer SiCO2 particles and on an ensemble of 7- and 28-micrometer monodisperse SiC particles upon exposure to radiation from a pulsed GOS-1001 laser with a wavelength of 1.06 micrometer are presented. A clearly pronounced wide maximum is typical of the spectra of acoustic pulse radiated by a plasma formation initiated on a single solid aerosol particle. The frequency of this maximum is shown to be dependent on the duration and shape of the radiated sound pulse. The total acoustic signal radiated by discrete plasma formations initiated on an ensemble of monodisperse particles injected in the laser beam caustic region represents a linear superposition of pulses from separate plasma formations. Its spectrum also has a wide maximum, whose amplitude and halfwidth are determined by the number of local plasma formations and the rms amplitude of acoustic pulses from separate plasma formations. The frequency of this maximum is shown to be dependent on durations and shapes of pulses from separate plasma formations.