skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: A model of laser imprinting

Abstract

Irradiation nonuniformities in direct-drive (DD) inertial confinement fusion experiments generate, or ''imprint,'' surface modulations that degrade the symmetry of the implosion and reduce the target performance. To gain physical insight, an analytical model of imprint is developed. The model takes into account the hydrodynamic flow, the dynamics of the conduction zone, and the mass ablation. The important parameters are found to be the time scale for plasma atmosphere formation and the ablation velocity. The model is validated by comparisons to detailed two-dimensional (2D) hydrocode simulations. The results of the model and simulations are in good agreement with a series of planar-foil imprint experiments performed on the OMEGA laser system [T.R. Boehly, D.L. Brown, R.S. Craxton et al., Opt. Commun. 133, 495 (1997)]. Direct-drive National Ignition Facility's [J.A. Paisner, J.D. Boyes, S.A. Kumpan, W.H. Lowdermilk, and M.S. Sorem, Laser Focus World 30, 75 (1994)] cryogenic targets are shown to have gains larger than 10 when the rms laser-irradiation nonuniformity is reduced by 2D smoothing by spectral dispersion (SSD) used in the current DD target designs. (c)

Authors:
 [1];  [1];  [1];  [1];  [1];  [1];  [1];  [2];  [3];  [3]
  1. Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299 (United States)
  2. Laboratory for Laser Energetics, Department of Physics and Astronomy, University of Rochester, Rochester, New York 14623 (United States)
  3. Laboratory for Laser Energetics, Department of Mechanical Engineering, Department of Physics and Astronomy, University of Rochester, Rochester, New York 14623 (United States)
Publication Date:
OSTI Identifier:
20216070
Resource Type:
Journal Article
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 7; Journal Issue: 5; Other Information: PBD: May 2000; Journal ID: ISSN 1070-664X
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; INERTIAL CONFINEMENT; IMPLOSIONS; LASER TARGETS; ICF DEVICES; OMEGA FACILITY; IGNITION SYSTEMS; ABLATION; LASER FUSION REACTORS; PLASMA SIMULATION; HYDRODYNAMICS; SHOCK WAVES; DESIGN; DEUTERIUM; THEORETICAL DATA

Citation Formats

Goncharov, V. N., Skupsky, S., Boehly, T. R., Knauer, J. P., McKenty, P., Smalyuk, V. A., Town, R. P. J., Gotchev, O. V., Betti, R., and Meyerhofer, D. D. A model of laser imprinting. United States: N. p., 2000. Web. doi:10.1063/1.874028.
Goncharov, V. N., Skupsky, S., Boehly, T. R., Knauer, J. P., McKenty, P., Smalyuk, V. A., Town, R. P. J., Gotchev, O. V., Betti, R., & Meyerhofer, D. D. A model of laser imprinting. United States. doi:10.1063/1.874028.
Goncharov, V. N., Skupsky, S., Boehly, T. R., Knauer, J. P., McKenty, P., Smalyuk, V. A., Town, R. P. J., Gotchev, O. V., Betti, R., and Meyerhofer, D. D. Mon . "A model of laser imprinting". United States. doi:10.1063/1.874028.
@article{osti_20216070,
title = {A model of laser imprinting},
author = {Goncharov, V. N. and Skupsky, S. and Boehly, T. R. and Knauer, J. P. and McKenty, P. and Smalyuk, V. A. and Town, R. P. J. and Gotchev, O. V. and Betti, R. and Meyerhofer, D. D.},
abstractNote = {Irradiation nonuniformities in direct-drive (DD) inertial confinement fusion experiments generate, or ''imprint,'' surface modulations that degrade the symmetry of the implosion and reduce the target performance. To gain physical insight, an analytical model of imprint is developed. The model takes into account the hydrodynamic flow, the dynamics of the conduction zone, and the mass ablation. The important parameters are found to be the time scale for plasma atmosphere formation and the ablation velocity. The model is validated by comparisons to detailed two-dimensional (2D) hydrocode simulations. The results of the model and simulations are in good agreement with a series of planar-foil imprint experiments performed on the OMEGA laser system [T.R. Boehly, D.L. Brown, R.S. Craxton et al., Opt. Commun. 133, 495 (1997)]. Direct-drive National Ignition Facility's [J.A. Paisner, J.D. Boyes, S.A. Kumpan, W.H. Lowdermilk, and M.S. Sorem, Laser Focus World 30, 75 (1994)] cryogenic targets are shown to have gains larger than 10 when the rms laser-irradiation nonuniformity is reduced by 2D smoothing by spectral dispersion (SSD) used in the current DD target designs. (c)},
doi = {10.1063/1.874028},
journal = {Physics of Plasmas},
issn = {1070-664X},
number = 5,
volume = 7,
place = {United States},
year = {2000},
month = {5}
}