We present an experimental study of the dynamics of shocks generated by the interaction of a double-spot laser in different kinds of targets: simple aluminum foils and foam–aluminum layered targets. The experiment was performed using the Prague PALS iodine laser working at 0.44 μm wavelength and irradiance of a few 1015 W/cm2. Shock breakouts for pure Al and for foam-Al targets have been recorded using time-resolved self-emission diagnostics. Experimental results have been compared with numerical simulations. The shocks originating from two spots move forward and expand radially in the targets, finally colliding in the intermediate region and producing a very strong increase in pressure. This is particularly clear for the case of foam layered targets, where we also observed a delay of shock breakout and a spatial redistribution of the pressure. The influence of the foam layer doped with high-Z (Au) nanoparticles on the shock dynamics was also studied.

We present a recent numerical analysis of impedance mismatch technique applied to carbon equation of state measurements. We consider high-power laser pulses with a Gaussian temporal profile of different durations. We show that for the laser intensity (${\approx }1{0}^{14} ~\mathrm{W} / {\mathrm{cm} }^{2} $) and the target design considered in this paper we need to have laser pulses with rise-time less than 150 ps.

We analyze the results of a recent experiment performed at the PALS laboratory and concerning ablation pressure at 0.44 µm laser wavelength measured at irradiance up to 2 × 1014 W/cm2. Using the code “ATLANT,” we have performed two-dimensional (2D) hydrodynamics simulations. Results show that 2D effects did not affect the experiment and also give evidence of the phenomenon of delocalized absorption of laser light.

We present a series of experimental results, and their interpretation, connected to various aspects of the hydrodynamics of laser produced plasmas. Experiments were performed using the Prague PALS iodine laser working at 0.44 μm wavelength and irradiances up to a few 1014 W/cm2. By adopting large focal spots and smoothed laser beams, the lateral energy transport and lateral expansion have been avoided. Therefore we could reach a quasi one-dimensional regime for which experimental results can be more easily and properly compared to available analytical models.

We present one-dimensional simulations performed using the multi group radiation hydro code MULTI with the goal of analyzing the target preheating effect under conditions similar to those of recent experiments aimed at studying the Equation of State (EOS) of various materials. In such experiments, aluminum is often used as reference material; therefore its behavior under strong shock compression and high-intensity laser irradiation (1013–1014 W/cm2) should be studied in detail. Our results reveal that at high laser irradiance, the laser energy available to induce shock pressure is reduced due to high X-rays generation. Simultaneously X-rays preheat the bulk of the reference material causing significant heating prior to shock propagation. Such effects induce deviations in shock propagation with respect to cold aluminum.

We have analyzed the shock wave propagation experiments performed at LULI and presented at ECLIM'94. The targets were aluminium foils with thickness from 5 to 25 μm. Simulations were performed with the SARA-1D multigroup radiation code. We have shown a small level of preheating caused by the absorption of X-rays with energies close to the K-edge of aluminum. Several sets of opacities were used in order to study this effect, including experimental values for cold aluminum. Simulations show a small level of visible emission induced by X-ray preheating before the arrival of the shock.