Characterization of plasma-induced shock waves

Abstract

Shock waves generated by laser-induced plasmas were investigated using a pump-and-probe technique. The shock peak pressure was determined from the measured shock velocity, the jump conditions, and the equation of state for water. Two plasma geometries, spherical and cylindrical, were investigated. The symmetry of the shock wave, in the near field, reflects the symmetry of the plasma. The conservation of momentum was used to derive expressions for the shock velocity, particle velocity and pressure vs. the distance (r) from the center of the plasma. For a cylindrical shock wave the shock pressure is proportional to 1/r. We have, also, applied the Rankine-Hugoniot expression to calculate the energy deposited behind the shock front. We found that a substantial fraction of the laser energy is deposited in the medium in the form of internal energy following the passage of a shock wave.