Characterization of a laser-produced plasma using the technique of point-projection absorption spectroscopy

The technique of point-projection spectroscopy has been shown to be applicable to the study of expanding aluminum plasmas generated by ∼80 ps laser pulses incident on massive, aluminum stripe targets of ∼125 μm width. Targets were irradiated at an intensity of 2.5±0.5×${10}^{13}$ W/${\mathrm{cm}}^2$ in a line focus geometry and under conditions similar to those of interest in x-ray laser schemes. Hydrogenic and heliumlike aluminum resonance lines were observed in absorption using a quasicontinuous uranium backlighter plasma. Using a pentaerythrital Bragg crystal as the dispersive element, a resolving power of ∼3500 was achieved with spatial resolution at the 5-μm level in frame times of the order of 100 ps. Reduction of the data for times up to 150 ps after the peak of the incident laser pulse produced estimates of the temperature and ion densities present, as a function of space and time. The one-dimensional Lagrangian hydrodynamic code m e d u s a coupled to the atomic physics non-local-thermodynamic-equilibrium ionized material package was used to simulate the experiment in planar geometry and has been shown to be consistent with the measurements.