Kinetic simulation of direct-drive capsule implosions and experiment comparisons

We have carried out simulations of direct-drive capsule implosion experiments conducted on Omega laser facility at the Laboratory of Laser energetics of the University of Rochester [1]. The capsules had a glass shell (SiO2) 4μm with an inner diameter of 1094μm. One was filled with equal parts of deuterium (D) and tritium (T) at 5.0 atmospheric pressure and the other capsule with 32% D, 32% T, and 36% He-3. The capsules were imploded with 60 laser beams with a square pulse length of 0.6ns of total energy of 16.3kJ. Spherical one-dimensional radiation hydrodynamic calculations with Hydra [2] and kinetic particle/hybrid simulations with LSP [3] were carried out for the post-shot analysis to compare neutron yield, yield ratio, and shell convergence in assessing the effects of plasma kinetic effects. The LSP simulations were initiated at 0.6ns with the density, temperature, and velocity profiles of the electrons, D, T, He-3, and SiO2 species based on output from Hydra simulations. The electrons are treated as a fluid while all the ion dynamics was simulated by the standard particle-in-cell technique. In our LSP simulations, we clearly observed species separation phenomenon between the deuterons, tritons and He-3 during the implosion but significantly less after the compression. The neutron yield, gamma bang-time and -width from the LSP simulations compared favorably with experiments while more significant discrepancies were found with Hydra simulations partly due to its inability to model species separation which leads to the reduction of reactivity during the implosion of the hot plasma. Detail comparison among the kinetic simulations, rad-hydro simulations, and experimental results will be presented. Additionally, we will present results from our calculations in which an attempt to model laser drive is included in our LSP simulations.