UNIFORM TARGET ILLUMINATION AND HIGH GAIN DIRECT DRIVE TARGET PERFORMANCE USING KrF LASERS

摘要

A two dimensional sliding zone implosion code is used to evaluate high gain direct drive target performance with mass imprinting by a non-uniform laser profile. Energy gains of 100-200 are possible with a 2-3.5 MJ laser if the laser imprinting generates less than a 300 A rms surface perturbation. KrF lasers with induced spatial incoherence (ISI) optical smoothing have the potential of producing a fluence variation of approximately 0.15-0.45% rms in a nanosecond time average. This should suffice to successfully implode a direct drive high gain target. The Nike KrF laser facility has begun operations in October 1994. The laser is expected to have a 0.3% rms fluence variation in a nanosecond time average, with a tilt of less than 1 %. Nike will verify the physics of imprinting and Rayleigh-Taylor growth, using flat targets with laser pulse conditions that mimic the initial stages of a high gain pellet implosion.