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Transport Physics and UQ

Transport Physics and UQ. Marvin L. Adams Texas A&M University CRASH Annual Review Ann Arbor, MI October 28-29, 2010. The integrated team has produced significant results this year. Collaboration has been fruitful and essential. UQ is a tightly integrated UM/TAMU/SFU effort.

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Transport Physics and UQ

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  1. Transport Physics and UQ Marvin L. Adams Texas A&M University CRASH Annual Review Ann Arbor, MI October 28-29, 2010

  2. The integrated team has produced significant results this year. • Collaboration has been fruitful and essential. • UQ is a tightly integrated UM/TAMU/SFU effort. • Theoretical understanding has advanced via collaboration (UM/TAMU). • Radiation has been an integrated UM/TAMU effort; this continues on more fronts as PDT & CRASH-MG mature. • This talk describes recent TAMU contributions. • Includes UQ, Radiation, and theory. • Much involves collaboration with UM and/or SFU; the remainder is part of integrated CRASH plan. We are an integral part of the team.

  3. Radiation effort is challenged by prohibition on coupling. • Key task is assessment of diffusion model error. • diffusion model error ≈ [hi-res transport] – [hi-res diffusion] • Must translate no-hydro results to rad-hydro problem • Must address diffusion discretization error • High-res transport tool is PDT (TAMU code). • We employ a no-hydro “CRASH-like” test problem. • We have developed a technique for using a transportcode (e.g., PDT) to help assess diffusion model error.

  4. CRASH-like test problem helps us assess model & discretization errors • Constant energy deposition to electrons at “shock” • Can assess effects of • discretization in energy, direction, space, and time • transport vs. diffusion • Current focus is on ablation layer in plastic • See Morel’s talk Au 19.3 g/cc plastic 1.43 g/cc Xe 0.1 g/cc .3125 mm Xe 0.018 g/cc Be 0.008 g/cc Xe 0.0059 g/cc electron energy source 4 mm

  5. PDT now solves CRASH-relevant problems. • Continually adding verification tests (McClarren poster) • Performance improvements have enabled solution of relevant problems • 40x serial speedup • 67% efficiency on 12k cores • Team effort (NE+CPSE at A&M) • see poster (“Massively Parallel ...) • There have been many other improvements • electron-energy sources, flexible initial and boundary conditions, CRASH opacities, better parallel I/O, improved visualization, diffusion preconditioner (debug phase), improved spatial discretizations, improved quadrature sets, etc.

  6. PDT can produce high-resolution transport results for this problem. • Example: • 50 energy groups, S18 quadrature (360 directions), 128 cells in first 0.5 micron of plastic (!), fully implicit solution • Weekend run,1024 cores • We are confident that we can assess discretization error and diffusion-model error for this problem • See Morel’s talk

  7. We’ve developed and applied advanced BMARS to CRASH UQ • Recent BMARS progress • Improved BMARS code, comparison with GP (see posters, papers, Stripling thesis) • Applied to H2D shock breakout (calibrated flux limiter, wall opacity, and Be EOS) • Built H1D emulator using BMARS and GP (paper accepted) • Contributors included Mallick, McClarren, Stripling, Ryu, Bingham, Holloway, and others from UM • See poster on calibration of H2D parameters for shock breakout (Stripling, et al.)

  8. We have developed and disseminated new theoretical results • Theory of thin/thick radiating shocks • Physics of Plasmas, McClarren/Drake/Morel/Holloway • Verification solutions • JQSRT, McClarren/Wohlbier • Also see McClarren poster • Diffusion model error in radiating shock • JQSRT, Drake/McClarren • Also see Morel talk

  9. We are improving discretization, iteration, parallel, and UQ methods • Assessment of diffusion model and numerical errors: underway; high priority in coming year • New STAPL: PDT transition has begun • Positive spatial discretization: Maginot, et al. poster • Long characteristics spatial discretization: Pandya, et al. poster • Provably optimal sweep schedules: Adams, et al. poster • Diffusion preconditioners for DFEM transport: in progress • Uncertainties from uncertain opacities: dimension-reduction effort in progress

  10. Next year should see further significant advances • PDT will become a more capable CRASH tool • more efficient temperature iterations, including use of diffusion preconditioner • RZ geometry; space-time characteristics; DG diffusion • more flexible source and boundary conditions (for verification tests) • Must scale well on BG/L • We will continue to advance UQ methods • include uncertainties in “x” inputs • improve emulator • assess model and discretization error • compensate for model error? • We will continue theoretical developments • more verification problems, including analytic 3T solutions • track-based sweeps • analyses of iteration and time-differencing methods

  11. Questions?

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