2-D Simulations of a 1-MJ CH-Foam Ignition Target on the NIF with 0.5 THz of 1-D Multi-FM SSD Bandwidth Using an Analytic Model

The 1-D multiple-frequency-modulator (Multi-FM) smoothing by spectral dispersion (SSD) system smoothes efficiently by taking advantage of multiple color cycles dispersed across the laser-beam cross section. An analytic SSD model has been enhanced to handle multiple modulators in one or both orthogonal directions. Previously, modeling Multi-FM required an ensemble of simulations that employed random flipping of phase states at every coherence time. The analytic model incorporates the necessary statistical averaging, so only a single simulation is required. An ensemble of random flipping simulations is compared to a simulation of the analytic model. The simulations use the 2-D radiation-hydrodynamics code \textit{DRACO} of a 1.0-MJ CH-foam ignition target on the NIF with 0.5 THz of bandwidth. Dynamic bandwidth reduction is used to increase the angular divergence during the foot of the pulse. This work was supported by the U.S. Department of Energy Office of Inertial Confinement Fusion under Cooperative Agreement No. DE-FC52-08NA28302.