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Title: Optical smoothing of laser imprinting in planar-target experiments on OMEGA EP using multi-FM 1-D smoothing by spectral dispersion

Direct-drive ignition on the National Ignition Facility (NIF) requires single-beam smoothing to minimize imprinting of laser nonuniformities that can negatively affect implosion performance. One-dimensional, multi-FM smoothing by spectral dispersion (SSD) has been proposed to provide the required smoothing [J. A. Marozas, J. D. Zuegel, and T. J. B. Collins, Bull. Am. Phys. Soc. 55, 294 (2010)]. A prototype multi-FM SSD system has been integrated into the NIF-like beamline of the OMEGA EP Laser System. Experiments have been performed to verify the smoothing performance by measuring Rayleigh–Taylor growth rates in planar targets of laser-imprinted and preimposed surface modulations. Multi-FM 1-D SSD has been observed to reduce imprint levels by ~50% compared to the nominal OMEGA EP SSD system. In conclusion, the experimental results are in agreement with 2-D DRACO simulations using realistic, time-dependent far-field spot-intensity calculations that emulate the effect of SSD.
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  1. Univ. of Rochester, Rochester, NY (United States)
  2. Univ. of Michigan, Ann Arbor, MI (United States)
  3. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
OSTI Identifier:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 23; Journal Issue: 9; Journal ID: ISSN 1070-664X
American Institute of Physics (AIP)
Research Org:
Univ. of Rochester, NY (United States). Lab. for Laser Energetics
Sponsoring Org:
Country of Publication:
United States
70 PLASMA PHYSICS AND FUSION TECHNOLOGY diffraction gratings; optical dispersion; x-ray optics; optical depth; speckle patterns