LLE Review 165

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Highlights

This volume of LLE Review 165 covers the period from October–December 2020. Articles appearing in this volume are the principal summarized results for long-form research articles. Readers seeking a more-detailed account of research activities are invited to seek out the primary materials appearing in print, detailed in the publications and presentations section at the end of this volume.

Highlights of research presented in this volume include the following:

• R. S. Craxton et al. describe polar-direct-drive exploding-pusher experiments at the National Ignition Facility (NIF). These targets are of interest as high-fluence sources of fusion neutrons (p. 1).
• D. H. Edgell et al. report on unabsorbed light measurements on OMEGA implosions using the 3~ gated optical imager diagnostic. The measurements are used to investigate absorption nonuniformity and coronal density profiles (p. 5).
• O. M. Mannion et al. use nuclear diagnostics to infer mode-one drive asymmetries in OMEGA implosions imparted by drive-beam mispointing (p. 8). A target offset was introduced to compensate the drive asymmetry and significantly improve hot-spot uniformity.
• J. J. Ruby et al. report on a Bayesian inference technique for inferring hot-spot plasma conditions and the corresponding uncertainties using a limited set of known parameters and a simplified physics model (p. 11).
• A. Shvydky et al. use density functional theory to calculate more-accurate values for the ionization state and index of refraction in the partially ionized material that is released after shock breakout (p. 13). The index of refraction is needed for inferring density profiles from interferograms of shock release taken on OMEGA EP.
• A. M. Hansen et al. report on measurements of cross-beam energy transfer saturation resulting from trapping-induced ion heating in TOP9 experiments (p. 16).
• R. K. Follett et al. use the LPSE code to calculate absolute thresholds for stimulated Raman scattering and two-plasmon decay driven by multiple broadband lasers at conditions relevant to OMEGA- and NIF-scale implosions (p. 19).
• J. Zhang et al. develop an analytic approach to calculating the reflection and transmission of light at a temporal boundary inside of a dispersive medium (p. 22).
• L. E. Crandall et al. report on equation-of-state measurements of CO₂ up to 800 GPa using laser-driven diamond-anvil-cell targets (p. 26).
• S. X. Hu et al. use density functional theory (DFT) calculations to determine stable high-pressure carbonaceous sulfur hydride compounds and to calculate their critical temperature for superconductivity (p. 29). The results are in good agreement with recent observations of room-temperature superconductivity at 270 GPa.
• V. V. Karasiev and S. X. Hu develop a novel free-energy DFT-based methodology for calculating x-ray absorption in warm dense plasmas. The new technique is used to build a first-principles opacity table for use in inertial confinement fusion (ICF) and high-energy–density physics applications (p. 32).
• J. Katz et al. build a transmitted beam diagnostic for diagnosing the time-resolved power spectrum of the wavelength-tunable TOP9 beam on OMEGA (p. 35).
• O. M. Mannion et al. develop a technique for reconstructing the hot-spot velocity, apparent ion temperature, and areal density in ICF implosions using the various neutron spectrometers on OMEGA (p. 39).
• Z. L. Mohamed et al. develop a forward-fitting technique for analyzing neutron time-of-flight data that includes an energy-dependent instrument response function (p. 42).
• M. J. Rosenberg et al. describe the progress in developing and implementing the scattered-light time-history diagnostic on the NIF (p. 46). The diagnostic will be deployed at 15 locations around the NIF target chamber for the purpose of measuring scattered light associated with stimulated Brillouin scattering, stimulated Raman scattering, and two-plasmon decay.
• C. Dorrer et al. develop a novel two-wavelength phase-matching technique for measuring the deuteration level of partially deuterated KPD crystals (p. 49). Precise knowledge of the deuteration level is required for modeling and optimizing of optical parametric amplifiers.
• I. A. Begishev et al. achieve high-efficiency fifth-harmonic generation in large-aperture ADP crystals cooled to 200 K in a two-chamber cryostat (p. 52).
• K. R. P. Kafka et al. report on laser-induced–damage testing of silica and hafnia monolayers. A pump-probe configuration is used to show the presence of two different time scales for defect initiation in silica (p. 57).
• J. Puth et al. summarize operations of the Omega Laser Facility during the first quarter of FY21 (p. 60).
• G. Pien et al. implement the remotePI protocol to allow for continued OMEGA 60 and OMEGA EP shot operations while complying with COVID-19 restrictions (p. 62).