POLYMER SHELL IMPLOSIONS.

The authors present a detailed investigation of ablatively driven gas-filled polymer shell targets irradiated by the 351-nm 2-kJ 4-TW Omega 24-beam laser system. The implosion of these targets was diagnosed with an extensive array of plasma, X-ray, and nuclear diagnostics. Detailed characterization of the multibeam laser output provided an estimate of the illumination nonuniformities imposed on target. Targets were fabricated from polystyrene or polyvinyl alcohol shells of 200-400- mu m diameter and 5-10- mu m wall thicknesses. Additional polymer layers and ultrathin metallic layers were added to reduce the initial aspect ratio and provide shine-through inhibition and weak X-ray signatures of ablation front penetration, respectively. A detailed comparison of the symmetry and performance of these target implosions has been made with the predictions of the one-dimensional (1-D) and 2-D hydrodynamic codes LILAC and ORCHID, respectively.