Generation of acoustic radiation by local plasma formations initiated by solid aerosol particles is one of the nonlinear effects of interaction between high-power laser radiation and atmospheric aerosols. In the present report, time histories of acoustic pulses radiated by discrete plasma formations, initiated under the action of focused laser radiation on a single solid aerosol particle suspended in the laser beam caustic region or on an ensemble of solid monodisperse aerosol particles injected in the laser beam caustic region, are analyzed. The measurements have shown that each local plasma formation radiates a single spherical acoustic pulse, and the total acoustic signal represents a linear superposition of pulses from separate plasma formations. The shape of a single acoustic pulse is satisfactorily approximated by a sinusoid for particles of micron sizes and reproduces a blast N-wave for particles with sizes varying from several tens to several hundreds of micrometers. The average amplitudes and half- periods of acoustic pulses depend linearly on the effective particle diameters with the proportionality coefficients determined by the particle material. The inequality of amplitudes and durations of positive and negative half-periods of acoustic pulses radiated by local plasma formations was also found.

Date Published: 29 December 2000
PDF: 6 pages
Proc. SPIE 4341, Seventh International Symposium on Atmospheric and Ocean Optics, (29 December 2000); doi: 10.1117/12.411947

Published in SPIE Proceedings Vol. 4341:
Seventh International Symposium on Atmospheric and Ocean Optics