The results of the experiments at the installation “PICO,” with thin foils heating by laser radiation pulses of nanosecond duration are reported. The Al foils with thickness in the range from 3 μ up to 40 μ were used as targets. The flux density was varied from 1013 W/cm2 to 1014 W/cm2. The sharp dependence of the portion of laser energy that passed through the target on foil thickness was observed. This phenomena was accompanied by a relatively small decrease of the passed radiation pulse duration. The anomalously high speed burning through of thin foil was observed in these experiments and the conclusion on the possible mechanism of this phenomena has been done on the base of comparison of experimental data with theoretical calculations. The observed phenomena can be interpreted with a conjecture about the local burning through of a target, in the small areas of the target surface, with many more values of flux density than the average one following laser radiation self-focusing and formation of “hot spots.”

A possibility of input of high-power laser pulse into a cavity through a hole was studied by means of 2D numerical calculations. Such tasks appear in view of investigation of the effective targets with internal input of energy (Bessarab et al. 1992; Basov et al. 1998), “cannon-ball” (Hogan 1989), “Greenhouse” targets (Gus'kov et al. 1995).

We have used two Euler codes “NUTCY” and “FAKEL” to model the problems of laser beam input into a cavity through the holes.

With a Petawatt class CPA laser of the LLNL Livermore or the proposed GSI (Darmstadt) type laser, interactions with matter can be studied in the upper 1020 W/cm2 regime. With such a laser focused into an underdense plasma, strong electron bursts with energies up to several 100 MeV are ejected in a forward direction. This leads to a comparable burst of bremsstrahlung radiation in the presence of high-Z material. Here, we discuss the corresponding γ-induced nuclear reactions including secondary particle production, including pions. Due to the threshold behavior in the production, and the advantage of delayed detection, we propose to employ these reactions for probing the initial plasma conditions.

The usual technique of the laser induced plasma spectroscopy (LIPS) spectra analysis relies on the use of calibration curves for quantitative measurements of plasma composition. However, LIPS calibration curves strongly depend on the material composition (the so-called matrix effect); thus, this standard approach to the LIPS spectra analysis is inadequate when precise information on unknown samples composition is required. In this paper we present a new procedure, based on LIPS, for calibration-free quantitative elemental analysis of materials. The new procedure, based on an algorithm developed and patented by IFAM-CNR, allows the overcoming of the matrix effect, yielding precise and accurate quantitative results without the need of calibration curves.

Interaction of relativistically strong laser pulses with under- and overdense plasmas is studied by 3D particle-in-cell simulations. We show that electrons in the underdense plasmas can be accelerated not only by the plasma wake field, but also by direct laser push in self-generated magnetic and electrostatic fields. These two mechanisms of acceleration manifest themselves in the electron energy spectra as two effective “temperatures.” We show that the fast electrons transport a significant part of the laser pulse power through the overdense plasma in the form of magnetized jets. We also find high collective stopping because of an anomalous resistivity of the plasma.

Opacity calculations for targets used in inertial confinement fusion (ICF) needs sophisticated atomic physics models, assuming a large number of configurations and transitions to simulate the plasma. Depending on the degree of accuracy for calculations of targets for ICF, some hydrodynamic-radiation codes use multifrequency opacities or well mean opacities.

In this work, using a sophisticated atomic physics code for LTE opacity calculations, that provides well multifrequency opacities or mean opacities, useful analytical opacity formulas for several single elements used in ICF have been generated, giving both Rosseland and Planck mean opacities as a function of the plasma parameters.

The calculations of 1014–1015 W/cm2 laser interaction with volume-structured agar-agar and Cu targets were performed. The influence of intrinsic X-ray plasma radiation on the propagation of thermal waves in such targets was investigated. It is shown that the velocity of heat transfer in agar-agar foam targets is increased due to X-ray preheating when a thin Cu layer is added.