Laser Imprint Reduction Using a Low-Density Foam Buffer as a Thermal Smoothing Layer at 351-nm Wavelength

Laser-nonuniformity-induced perturbation growth has been measured on planar foam-buffered plastic (CH) targets irradiated with 351-nm laser radiation. The maximum observed perturbation growth was reduced by about $50%$ by the foam buffer. Rayleigh-Taylor unstable growth of intentional mass modulations was minimally changed by the addition of the foam buffer. We conclude that the reduction of laser-induced perturbation growth is a result of a reduction in the perturbation seed amplitude rather than any changes in the growth rate in the solid due to preheating by radiation or shocks caused by the presence of the foam buffer.