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Title: Direct-drive laser target designs for sub-megajoule energies

Abstract

New direct-drive laser target designs with KrF laser light take advantage of the shorter wavelength to lower the laser energy required for substantial gain (>30x) to sub-MJ level. These low laser-energy pellets are useful in systems that could form an intermediate step towards fusion energy, such as the proposed Fusion Test Facility [S. P. Obenschain et al., Phys. Plasmas 13, 056320 (2006)]. The short wavelength laser should allow higher intensity (and higher pressure) without increasing the risk of laser-plasma instabilities. The higher pressure in turn allows higher velocities to be achieved while keeping the low aspect ratios required for hydrodynamic stability. The canonical laser energy has been chosen to be 500 kJ. A target design is presented with various laser pulse shapes and both 1D and 2D simulation results are shown. The sensitivity of these targets to both low-mode and high-mode perturbations is examined. The analysis and simulations in this paper indicate that significant gain (G=57) can be achieved for these targets even in the presence of hydrodynamic instabilities.

Authors:
; ; ; ; ; ; ; ;  [1];  [2];  [2];  [2]
  1. Plasma Physics Division, Naval Research Laboratory, Washington, D.C. 20375 (United States)
  2. (United States)
Publication Date:
OSTI Identifier:
20975073
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 14; Journal Issue: 5; Other Information: DOI: 10.1063/1.2730503; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ASPECT RATIO; DESIGN; GAIN; KRYPTON FLUORIDE LASERS; LASER TARGETS; PLASMA; PLASMA INSTABILITY; PLASMA PRESSURE; PULSE SHAPERS; SIMULATION; TEST FACILITIES; THERMONUCLEAR REACTORS; WAVELENGTHS

Citation Formats

Colombant, D. G., Schmitt, A. J., Obenschain, S. P., Zalesak, S. T., Velikovich, A. L., Bates, J. W., Fyfe, D. E., Gardner, J. H., Manheimer, W., LCP and FD, Naval Research Laboratory, Washington, D.C. 20375, BRA, Springfield, Virginia, and RSI, Lanham, Maryland 20706. Direct-drive laser target designs for sub-megajoule energies. United States: N. p., 2007. Web. doi:10.1063/1.2730503.
Colombant, D. G., Schmitt, A. J., Obenschain, S. P., Zalesak, S. T., Velikovich, A. L., Bates, J. W., Fyfe, D. E., Gardner, J. H., Manheimer, W., LCP and FD, Naval Research Laboratory, Washington, D.C. 20375, BRA, Springfield, Virginia, & RSI, Lanham, Maryland 20706. Direct-drive laser target designs for sub-megajoule energies. United States. doi:10.1063/1.2730503.
Colombant, D. G., Schmitt, A. J., Obenschain, S. P., Zalesak, S. T., Velikovich, A. L., Bates, J. W., Fyfe, D. E., Gardner, J. H., Manheimer, W., LCP and FD, Naval Research Laboratory, Washington, D.C. 20375, BRA, Springfield, Virginia, and RSI, Lanham, Maryland 20706. Tue . "Direct-drive laser target designs for sub-megajoule energies". United States. doi:10.1063/1.2730503.
@article{osti_20975073,
title = {Direct-drive laser target designs for sub-megajoule energies},
author = {Colombant, D. G. and Schmitt, A. J. and Obenschain, S. P. and Zalesak, S. T. and Velikovich, A. L. and Bates, J. W. and Fyfe, D. E. and Gardner, J. H. and Manheimer, W. and LCP and FD, Naval Research Laboratory, Washington, D.C. 20375 and BRA, Springfield, Virginia and RSI, Lanham, Maryland 20706},
abstractNote = {New direct-drive laser target designs with KrF laser light take advantage of the shorter wavelength to lower the laser energy required for substantial gain (>30x) to sub-MJ level. These low laser-energy pellets are useful in systems that could form an intermediate step towards fusion energy, such as the proposed Fusion Test Facility [S. P. Obenschain et al., Phys. Plasmas 13, 056320 (2006)]. The short wavelength laser should allow higher intensity (and higher pressure) without increasing the risk of laser-plasma instabilities. The higher pressure in turn allows higher velocities to be achieved while keeping the low aspect ratios required for hydrodynamic stability. The canonical laser energy has been chosen to be 500 kJ. A target design is presented with various laser pulse shapes and both 1D and 2D simulation results are shown. The sensitivity of these targets to both low-mode and high-mode perturbations is examined. The analysis and simulations in this paper indicate that significant gain (G=57) can be achieved for these targets even in the presence of hydrodynamic instabilities.},
doi = {10.1063/1.2730503},
journal = {Physics of Plasmas},
number = 5,
volume = 14,
place = {United States},
year = {Tue May 15 00:00:00 EDT 2007},
month = {Tue May 15 00:00:00 EDT 2007}
}