A high-irradiance short pulsed laser was used to generate hemispherical shock waves in planar targets. A linear relationship was obtained between the laser energy for threshold spall conditions (EL) and the cubic target thickness (d): EL = 45.3d3 + 4.9, where EL is in J and d is in mm. It is found that the laser-induced ablation pressure decays with the distance to a power slightly greater than 2.

Nonstationarity of stimulated Raman backscattering in a finite homogeneous plasma slab is examined. Slowly varying envelope equations are analyzed taking into account a damping and a convection of an electron plasma wave, with a nonzero source boundary condition assumed. The linear analysis method is used for examination of stability of saturated stationary amplitude solutions. When linear wave damping is sufficiently small or absent, these solutions are spatially periodic and appear linearly unstable to small perturbations. However, a direct numerical simulation of the backscattering process in a lossless case shows that the system tends to quasistationary state with maximum reflectivity (R → 1). If the electron plasma wave damping exceeds a certain critical value, a spatially aperiodic solution raises and the Raman backscattering process becomes stable.

A simplified model for determining the performance of large krypton-fluoride laser amplifiers is presented. The model includes a straightforward treatment of the controlling kinetics, an exact solution for energy extraction, and an approximation to amplified spontaneous emission losses; it can be easily programmed to run on personal computers. The inclusion of the controlling basic physics for KrF lasers makes the model ideally suited for the many calculations that are necessary to optimize the design of a specific amplifier. The basic parameters determined in the model are compared to experimental data wherever possible, and the large amplifier performance predictions are compared to the results from the most sophisticated kinetics and a 3-D extraction model that includes a full treatment of losses due to amplified spontaneous emission.

A novel α-particle backlighting technique has been developed to diagnose laser plasmas, enabling small changes in the thickness modulation to be measured, down to ~0.1 μm. In this technique, a laser-driven implosion of a D–T target produces a bright pulse of α-particles that is used to shadow a separately driven foil. Each α-particle loses range in the foil, and each such measurement forms an individual local determination of the foil thickness at the time of passage of the particles. A shadow image of the driven foil can also be produced, of spatial resolution limited by source size and multiple Coulomb scattering in the driven plasma. The technique is illustrated here with a preliminary study of fluid instabilities in laser-accelerated planar foils. Foils were accelerated using both unsmoothed and smoothed laser drive beams. Foils driven by beams smoothed by random-phase plates showed a much reduced modulation.

The experimental results on high-power ion beams (HPIB) generation in a plasma-filled, spherical-focusing diode with self-magnetic insulation that was placed for a load at nanosecond accelerator PARUS of 0.2-TW power and 60-ns pulse duration (in a matched load case) are given. The regimes of plasma-filled diode operation and generation of the ion beam were investigated. For optimal time delay between the plasma gun's pulse and accelerator firing, the stable operation in the plasma opening switch mode with a power enhancement factor of 2.3 and efficiency of ion beam generation of 20–25% was obtained. The maximal value of the ion current density reached in the focal plane was 15 kA/cm2.