Abstract: The availability of ultrashort (100 fs) high intensity lasers capable of producing focused intensities in excess of 10$+18$/ W/cm$+2$/ provides many new opportunities in studying the interaction of radiation with matter. We describe a new laser plasma facility constructed around a Cr:LiSAF laser system currently capable of output energies of approximately 1 J in times of approximately 100 fs. This facility will be directed initially towards basic studies of the interaction of intense ultrashort laser pulses with dense plasmas, and the generation and application of intense hard x-ray point sources. The laser system we have developed for this facility, uses the new solid- state laser material, Cr:LiSAF. This material has many advantages for the generation of intense ultrashort laser pulses. The spectral gain bandwidth is sufficiently broad for the amplification of pulses shorter than 100 fs in duration. Its florescence lifetime is long enough to permit the use of conventional flashlamp pumping, and its emission cross- section is such that it provides small signal gains high enough to allow its use in high powered chirped pulsed amplification laser architectures. The material can now be fabricated into laser rods up to 25 mm in diameter with low scattering losses and its Cr concentrations can be varied to optimize the small signal gain for specific pump cavities. These factors taken together allow the design of a 100 fs high intensity oscillator-laser system that is simpler in architecture than those based on Ti:sapphire or KrF. Moreover the use of Cr:LiSAF laser crystal elements should enable the generation of much higher powers. In principle as high as 1 PW should be achievable with a laboratory with this approach. Modifications currently being implemented onto our Cr:LiSAF laser system include improvements to pulse contrast, energy extraction, beam uniformity and focusability. The system will soon be incorporated with a 52- port precision target chamber that will be equipped with a broad array of x ray and plasma diagnostics. Several research programs are being designed around this facility. Two of these programs, those relating to the use of hard x rays for the analysis of shock phenomena in solids and the general physics of extremely high magnetic fields are presented. !40
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