Phebus as a test-bed for a Megajoule laser facility

This paper reviews the Precision Phebus operation during the last two years. The Phebus facility has been in continuous use for laser-target interaction experiments since it was completed in December 1985 and since couple of years it is also used for laser science experiments such as beam smoothing experiments. In 1993 it has fires more than 900 system shots. Operating this laser system at large optical powers and energies requires continuously improvements of the facility characteristics such as the beam targeting accuracy and beam uniformity. During high power shots, several nonlinear optical processes are also observed that, if not understood and controlled, limit the performance of the system. To point out some of them in view of the Megajoule program is a challenge on a system the size of Phebus. We emphasize in this paper first the study of the effects of failed flash lamps on the output characteristics of the laser pulse, then the operating conditions with long pulses (3 ns) and finally some aspects of beam smoothing. (Authors). 5 refs., 8 figs