Fokker-Planck Modeling of Heat Conduction in NIF Hohlraums We use the Vlasov-Fokker-Planck code OSHUN to model electron heat conduction in a realistic plasma profile for a NIF “rugby- shaped” hohlraum. Please attend my talk on 25 August 2015 to see NIF results. Andrew H. Dublin 1,2 , David J. Strozzi 1 , Adam Tableman 3 , Benjamin Winjum 3 Lawrence Livermore National Laboratory 1 | University of Rochester 2 | University of California at Los Angeles 3 Results: Introduction: Methods: • Electron heat conduction is a key process in inertial fusion targets, like NIF hohlraums. • Radiation-hydrodynamics codes routinely use the collisional Spitzer-Harm model, with an ad-hoc “flux limit” to match data. • Kinetic and non-local effects can sometimes be important. • The code OSHUN (Tzoufras et. al, Phys. Plasmas 2013), developed at UCLA, solves the Vlasov-Fokker-Planck equation: • OSHUN uses the spherical harmonic expansion: • Spherical coordinates: • Electron-ion collision operator (electron-electron is more complicated) • Thermal conductivity κ: • Spitzer-Härm, local collisional result (Z i >>1): • We ran OSHUN on the 1-D green path from above: Z=2 helium • We compare OSHUN results with Spitzer-Härm theory. LLNL-POST-675603 This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. Lasnex simulation of NIF hohlraum. We study heat conduction along the green path. Gold wall Capsule: ablator and fusion fuel Helium plasma electron-electron collisions electron-ion collisions f e (r,p,t) = electron distribution Discussion: • OSHUN displays non-local reduction in thermal conductivity for large temperature gradients. • Future work: 2D simulations, mobile ions, and gold wall conditions. Spitzer-Härm Result Non-local reduction in κ λ 0 = mean free path 1-D NIF profile for OSHUN 4.5 0.12 n e T e 0 0 0.05 Non-locality Parameter 0