A laserhyphen;produced plasma generates blast waves as it expands supersonically into a stationary photoionized background gas (N2) at a pressure of 1ndash;5 Torr.1Using a combination of spectroscopic and interferometric measurements, timehyphen; and spacehyphen;resolved values of the temperature and density are obtained. This study was performed on targets in the NRL Pharos III laser facility with laser energies of 20ndash;120 J and pulse durations of sim;5 ns. A 1hyphen;m spectrograph equipped with three photomultiplier channels, which are calibrated on an absolute scale, is used for the spectroscopic measurements. The interferometry is done with a foldedhyphen;wavefront interferometer. It uses an optical probe pulse at 5270 Aring; that is split off of the main laser pulse, reduced in pulse duration (sim;300 ps), and time delayed. Interferometric measurements can be made simultaneously with the spectroscopic measurements. Experimental data and the technique of analysis will be shown. This work was supported by the Defense Nuclear Agency.
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