Recent Developments in Ignition Target Designs for the National Ignition Facility

Work on design of ignition targets for the National Ignition Facility (NIF) has progressed in three areas. First, hohlraums have been re-optimized taking advantage of improvements in efficiency in several areas: use of high albedo material mixtures in the hohlraum wall; optimizing the laser entrance hole; optimizing the case-to-capsule ratio; and taking advantage of increased efficiency of longer pulses. These changes, in combination, allow for the possibility of quite high yields ({approx}100 MJ),gains (>40) and significantly more margin for ignition on NIF. Second, work has continued on specifications for target fabrication. Third, detailed design and analysis has been done on targets for the commissioning phase of NIF, when only 96 beams are available. We find excellent hydrodynamic similarity is possible with sub-scale cryogenic targets. These targets can be used to test all of the physics of full-scale ignition targets in detail except, perhaps, for ignition itself