A path to a hydro-equivalent ignition demonstration for laser direct-drive on the OMEGA laser

ORAL · Invited

Abstract

Laser direct drive (LDD) offers significant advantages in terms of target simplicity, improved energy coupling and large fuel masses over indirect drive. However, performance degradations from hydrodynamic and laser-plasma instabilities seeded and driven by the direct illumination pose limitations on the parameter space available for achieving ignition. Recent advances in target design and prediction capability using statistical modeling led to significant improvements in performance to achieve a Lawson triple product that hydrodynamically scales to about 90% of the value required for ignition if equivalent laser-target coupling is achieved at the 2 MJ energy level of the NIF. New design improvements are identified to forge a path forward for a hydro-equivalent ignition demonstration. The first is related to controlling the mode-1 asymmetry through a novel analysis that quantifies the individual contributions from target offset, laser mispointing, power imbalance and a residual systematic mode. It uses flow measurements, mode-1 simulations and statistical regressions over a large database of shots to determine the optimum target offset to be applied in the experiments to minimize mode-1 amplitude. The second improvement comes from cooling the ice layer below the triple point right before shot time. This leads to lower DT vapor densities and higher convergence. While subcooling is an effective way to increase areal density, it requires mitigation of mode 1 due to greater sensitivity to low modes. One implosion with 2.5K subcooling achieved record hot spot pressure. The third improvement comes from a new formulation of the statistical model (SM) used to accurately predict target performance directly from input parameters such as laser pulse shape and target specifications. This new SM formulation provides direct guidance on target dimensions and laser beam to target radius to achieve the highest performance on the OMEGA laser.

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Presenters

  • Aarne Lees

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

Authors

  • Aarne Lees

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

  • Riccardo Betti

    Laboratory for Laser Energetics, University of Rochester, Laboratory for Laser Energy, Rochester, NY, USA.

  • Varchas Gopalaswamy

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

  • James P Knauer

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

  • Luke A Ceurvorst

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

  • Dhrumir P Patel

    University of Rochester

  • Pericles Silouanos Farmakis

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

  • Rahman Ejaz

    Laboratory for Laser Energetics, University of Rochester

  • Ka Ming Woo

    Laboratory for Laser Energetics, University of Rochester

  • Duc M Cao

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

  • Cliff A Thomas

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

  • Igor V Igumenshchev

    Lab for Laser Energetics

  • P. B Radha

    Los Alamos National Laboratory, University of Rochester

  • Kenneth S Anderson

    Laboratory for Laser Energetics, University of Rochester

  • Timothy J Collins

    Laboratory for Laser Energetics, University of Rochester

  • Valeri N Goncharov

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

  • Rahul C Shah

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

  • Chad Forrest

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

  • Christian Stoeckl

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

  • Vladimir Glebov

    Lab for Laser Energetics

  • Dana H Edgell

    University of Rochester - Laboratory for Laser Energetics

  • Michael J Rosenberg

    University of Rochester Laboratory for Laser Energetics (LLE), Laboratory for Laser Energetics, University of Rochester, University of Rochester

  • Kristen Churnetski

    University of Rochester

  • Peter V Heuer

    Laboratory for Laser Energetics

  • Sean P Regan

    Laboratory for Laser Energetics, University of Rochester

  • Roger T Janezic

    Laboratory for Laser Energetics, University of Rochester

  • David R Harding

    University or Rochester Laboratory for Laser Energetics, Laboratory for Laser Energetics

  • Mark J Bonino

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

  • Siddharth Sampat

    Laboratory for Laser Energetics

  • Maria Gatu Johnson

    Plasma Science and Fusion Center, Massachusetts Institute of Technology, MIT

  • Chikang Li

    Massachusetts Institute of Technology MIT

  • Christopher W Wink

    Massachusetts Institute of Technology

  • Johan A Frenje

    Massachusetts Institute of Technology