Results of OMEGA Direct Drive and Polar Direct Drive implosions using 2-D simulations

The Defect Induced Mix Experiment (DIME) campaign¹ was a series of OMEGA capsule implosions designed to study mix in the present of quasi 2-D defects, such as equatorial trenches and fake fill tubes. The results could be compared to 2-D simulations. The capsules had ~430 micron outer radius, with 15 to 20 micron thick CH ablators and a 5 atm deuterium gas fill. These capsules were imploded in both 60 beam direct drive and 40 beam Polar Direct Drive (PDD) configurations with a 1 ns square pulse. The polar direct drive results were used to design subsequent National Ignition Facility PDD capsule implosions. We use the xRAGE Eulerian Adaptive-Mesh-Refinement computer code to model these implosions in 2-D with laser ray tracing and energy deposition. We find that we need to adjust the relative laser drive weight of the two beam angles in polar direct drive to account missing Cross Beam Energy Transfer physics. We compare our results to DD neutron yields, burn weighted DT Tion value, burn width, and synthetic x-ray emission images. We match most results for the direct drive capsules, but have more trouble matching the data in our PDD simulations.



¹M.J. Schmitt et al., Phys. Plasmas, 20, 056310 (2013)