Ejecta particle size distributions for shock loaded Sn and Al targets

When a shock wave interacts at the surface of a metal sample "ejected matter" (ejecta) can be emitted from the surface. The mass, size, shape, and velocity of the ejecta varies depending on the initial shock conditions and the material properties of the target. To understand this phenomena, experiments have been conducted at the Pegasus Pulsed Power Facility (PPPF) located at Los Alamos National Laboratory (LANL). The facility is used to implode cylinders to velocities of many mm//spl mu/sec. The driving cylinder impacts a smaller target cylinder where shock waves of many hundreds of kilobars can be reached and ejecta formation proceeds. The ejecta particle sizes are measured using an in-line Fraunhofer holography technique. Over the years much work has gone into characterizing ejecta mass, but very little has been done to understand the particle size distributions. In this report, ejecta particle size distributions are presented for shocked Al and Sn targets at pressures of 300 kb and 400 kb respectively. For the first time, particle distributions that results from microjet production are presented. Results from these experiments are presented along with predictions from percolation theory.