COMPUTATIONAL MODELING OF DIRECT-DRIVE FUSION PELLETS AND KRF-DRIVEN FOIL EXPERIMENTS

FAST is a radiation transport hydrodynamics code that simulates laser matter interactions of relevance to direct-drive laser fusion target d esign. FAST solves the Euler equations of compressible dow using the F lux-Corrected Transport finite volume method. The advection algorithm provides accurate computation of flows from nearly incompressible vort ical flows to those that are highly compressible and dominated by stro ng pressure and density gradients. In this paper we describe the numer ical techniques and physics packages. FAST has also been benchmarked w ith Nike laser facility experiments in which linearly perturbed, low a diabat planar plastic targets are ablatively accelerated to velocities approaching 10(7) cm/s. Over a range of perturbation wavelengths, the code results agree with the measured Rayleigh-Taylor growth from the linear through the deeply nonlinear regimes. FAST has been applied to the two-dimensional spherical simulation design to provide surface fin ish and laser bandwidth tolerances for a promising new direct-drive pe llet that uses a foam ablator.