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The Impact of Target-Layer Imperfections on Performance Sensitivity to Laser Imprint for Direct-Drive Inertial Confinement Fusion (DDICF) Implosions on OMEGA.

ORAL

Abstract

Recent experimental results showed that the highest performing class of DDICF implosions on OMEGA at adiabat ~4.5 are not dominated by degradation from laser imprint1, but are significant at adiabat~3.5 . This was shown by measuring changes in neutron yield and neutron-averaged areal density (ρR) to varying levels of laser spot smoothing by spectral dispersion (SSD) and observing performance saturation for sufficiently high SSD bandwidth. We report on a 2-D simulation study with DRACO2 seeking to reproduce these trends by introducing target imperfections via a surface-roughness spectrum, in addition to laser imprint. While previous DRACO simulation results with laser imprinting alone did not show performance saturation at the SSD levels observed, a mechanism to reproduce it could be done through an additional, high-mode perturbation source that is independent of SSD. The perturbation added is characterized by <1 um amplitude, high-mode imperfections (l=60 to 120 spectrum suggested by 2D VISAR measurements3) at the fuel-ablator interface, in addition to a NIF standard surface roughness spectrum. The results from this study are valuable for determining what perturbation seeds need to be included in simulations in order to create scientifically credible performance extrapolations for future target designs.

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Publication: J. P. Knauer, R. Betti, D. Patel, V. Gopalaswamy, D. Cao, A. Lees, A. Shvydky, M. J. Bonino, E. M. Campbell, T. J. B. Collins, C. J. Forrest, V. Yu. Glebov, V. N, Goncharov, D. R. Harding, J. A. Marozas, F. J. Marshall, P. W. McKenty, J. L. Peebles, P. B. Radha, S. P. Regan, T. C. Sangster, C. Stoeckl, M. Gatu Johnson, J. A. Frenje, R. D. Petrasso, L. Aghaian, J. Murray, B. Serrato, D. Guzman, M. Hoppe, C. Shuldberg, and M. Farrell, presented at the 64th American Physical Society Division of Plasma Physics, Spokane, WA, 17–21 October 2022 (invited). <br><br>P. B. Radha, V. N. Goncharov, T. J. B. Collins, J. A. Delettrez, Y. Elbaz, V. Yu. Glebov,R. L. Keck, D. E. Keller, J. P. Knauer, J. A. Marozas, F. J. Marshall, P. W. McKenty, D.D. Meyerhofer, S. P. Regan, T. C. Sangster, D. Shvarts, S. Skupsky, Y. Srebro, R. P. J.Town, and C. Stoeckl, Phys. Plasmas12, 032702 (2005).<br><br>J. L. Peebles, S. X. Hu, W. Theobald, V. N. Goncharov, N. Whiting, E. M. Campbell, T. R. Boehly, S. P. Regan, P. M. Celliers, S. J. Ali, and G. Duchateau, presented at the 61st Meeting of the American Physical Society Division of Plasma Physics, Fort Lauderdale, FL, 21–25 October 2019.

Presenters

  • Duc M Cao

    University of Rochester, Laboratory for Laser Energetics, U. Rochester/LLE

Authors

  • Duc M Cao

    University of Rochester, Laboratory for Laser Energetics, U. Rochester/LLE

  • James P Knauer

    University of Rochester

  • Riccardo Betti

    Laboratory for Laser Energy, Rochester, NY, USA., University of Rochester, LLE, Univ of Rochester

  • Dhrumir P Patel

    University of Rochester

  • Varchas Gopalaswamy

    Laboratory for Laser Energetics - Rochester

  • Aarne Lees

    University of Rochester

  • Alexander Shvydky

    Lab for Laser Energetics, Laboratory for Laser Energetics, Laboratory for Laser Energetics, University of Rochester

  • Cliff A Thomas

    University of Rochester

  • John A Marozas

    Laboratory for Laser Energetics, University of Rochester

  • Patrick m McKenty

    Laboratory for Laser Energetics, University of Rochester

  • P. B Radha

    Laboratory for Laser Energetics - Rochester, University of Rochester, Laboratory for Laser Energetics

  • TImothy J Collins

    University of Rochester

  • Valeri N Goncharov

    University of Rochester, Laboratory for Laser Energetics

  • Chad J Forrest

    LLE, Lab for Laser Energetics, University of Rochester, University of Rochester, Laboratory for Laser Energetics, Laboratory for Laser Energetics

  • Christian Stoeckl

    University of Rochester

  • Vladimir Glebov

    Lab for Laser Energetics, University of Rochester

  • Mark J Bonino

    Laboratory for Laser Energetics, University of Rochester, Laboratory for Laser Energetics, University of Rochester

  • David R Harding

    Laboratory for Laser Energetics, Laboratory for Laser Energetics, University of Rochester, University of Rochester, Laboratory for Laser Energetics, University of Rochester

  • Frederic J Marshall

    University of Rochester

  • Jonathan L Peebles

    Laboratory for Laser Energetics

  • Sean P Regan

    Laboratory for Laser Energetics, University of Rochester

  • Maria Gatu-Johnson

    MIT

  • Johan A Frenje

    Massachusetts Institute of Technology MIT

  • Richard D Petrasso

    Massachusetts Institute of Technology MIT