Laser uniformity and hydrodynamic stability experiments at the OMEGA laserfacility

Experiments to demonstrate the effects of various beam-smoothing techniques have been performed on the 60-beam, 30-kJ UV OMEGA laser system. These inc lude direct measurements of the effect beam-smoothing techniques have on la ser beam nonuniformity and on both planar and spherical targets. Demonstrat ed techniques include polarization smoothing and "dual-tripler" third-harmo nic generation required for future broad bandwidth (similar to1 THz) smooth ing by spectral dispersion (SSD). The effects of improvements in single-bea m uniformity are clearly seen in the target-physics experiment which also s how the effect of the laser pulse shape on the efficacy of SSD smoothing. S aturation of the Rayleigh-Taylor (RT) growth of the broad-bandwidth feature s, in agreement with the Haan model (Haan, 1989),produced by laser imprinti ng has also been observed.