Self-emission x-ray shadowgraphy provides a method to measure the ablation-front trajectory and low-mode nonuniformity of a target imploded by directly illuminating a fusion capsule with laser beams. The technique uses time-resolved images of soft x-rays (${>}1$ keV) emitted from the coronal plasma of the target imaged onto an x-ray framing camera to determine the position of the ablation front. Methods used to accurately measure the ablation-front radius (${\it\delta}R=\pm 1.15~{\rm\mu}\text{m}$), image-to-image timing (${\it\delta}({\rm\Delta}t)=\pm 2.5$ ps) and absolute timing (${\it\delta}t=\pm 10$ ps) are presented. Angular averaging of the images provides an average radius measurement of ${\it\delta}(R_{\text{av}})=\pm 0.15~{\rm\mu}\text{m}$ and an error in velocity of ${\it\delta}V/V=\pm 3\%$. This technique was applied on the Omega Laser Facility [Boehly et al., Opt. Commun. 133, 495 (1997)] and the National Ignition Facility [Campbell and Hogan, Plasma Phys. Control. Fusion 41, B39 (1999)].

Experiments to demonstrate the effects of various beam-smoothing techniques have been performed on the 60-beam, 30-kJ UV OMEGA laser system. These include direct measurements of the effect beam-smoothing techniques have on laser beam nonuniformity and on both planar and spherical targets. Demonstrated techniques include polarization smoothing and “dual-tripler” third-harmonic generation required for future broad bandwidth (∼1 THz) smoothing by spectral dispersion (SSD). The effects of improvements in single-beam uniformity are clearly seen in the target-physics experiments, which also show the effect of the laser pulse shape on the efficacy of SSD smoothing. Saturation of the Rayleigh-Taylor (RT) growth of the broad-bandwidth features, in agreement with the Haan model (Haan, 1989), produced by laser imprinting has also been observed.