Application of photon Doppler velocimetry for characterization of ejecta from shock-loaded samples

We consider the problem of recovering the physical parameters of ejecta from data of photon Doppler velocimetry (PDV). The results of PDV measurements of ejecta production from shock-loaded Pb samples are presented. Shockwaves in the samples were generated by an accelerated flyer-plate. Depending on the sample thickness, the shock-breakout pressure varied from 27.5 to 43 GPa. The ejecta transport occurred in the air. The spectral profile J(omega) of heterodyne beats underlies our analysis of the experiments. The noise-free component of vertical bar J(omega)vertical bar 2 is shown to obey the transport equation which accounts for multiple scattering and absorption of the probing beam in the cloud of moving particles. This provides a means for theoretical modeling of PDV data. Varying the values of the free-surface velocity and the parameters of the velocity distribution of ejecta, we fit the calculated spectrum to the PDV-measured one. We apply this method to time-resolved PDV spectra and, based on the ejecta optical model, recover the values of the free-surface velocity, the areal density, and the density-velocity distribution of ejecta. Published by AIP Publishing.