We report measurements of x-ray scattering cross sections for dense plasmas created by subjecting aluminum foils to strong laser-driven shocks. A narrow cone of quasimonochromatic x-rays at approximately 4.75 keV was used to probe the shocked part of the foil and scattered photons were detected with a CCD camera. The scattering cross section shows a clear peak, indicating diffraction from the plasma. Analysis and simulation of the data suggest that radiative heating and electron-ion energy exchange are important factors in the plasma production.

A method for the self-consistent solution of the hydrodynamic, excitation and ionization equations describing a laser-produced plasma is presented. The coupling of atomic processes and the free electron energy balance equation in a one-dimensional Lagrangian model is described. Transitions between excited as well as the ground states are included within the average-atom approximation. The resulting model is used to calculate ionization and population inversion in Delta n not=0 recombination X-ray laser experiments. With the addition of a steady-state collisional radiative model for Delta n=0 transitions, collisional X-ray lasers have also been modelled.

Fast electron generation and propagation were studied in the interaction of a green laser with solids. The experiment, carried out with the LULI TW laser (350 fs, 15 J), used K(alpha) emission from buried fluorescent layers to measure electron transport. Results for conductors (Al) and insulators (plastic) are compared with simulations: in plastic, inhibition in the propagation of fast electrons is observed, due to electric fields which become the dominant factor in electron transport.

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Exploiting the high absorption efficiency of intense, ultrashort laser pulses in gases of atomic clusters we have created plasma filaments with temperatures of .1 keV and electron densities in excess of 10 20 cm 23 . Using picosecond laser pulses, we have interferometrically measured the temporal and spatial evolution of the electron density in these plasmas on a fast ͑,50 ps͒ time scale. Our measurements indicate that nonlocal heat transport by hot electrons drives a fast ionization wave, and the data agree well with a nonlocal heat transport model. [S0031-9007(97)