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Title: Assessing the prospects for achieving double-shell ignition on the National Ignition Facility using vacuum hohlraums

Abstract

The goal of demonstrating ignition on the National Ignition Facility [J. D. Lindl et al., Phys. Plasmas 11, 339 (2003)] has motivated a revisit of double-shell (DS) targets as a complementary path to the cryogenic baseline approach. Expected benefits of DS ignition targets include noncryogenic deuterium-tritium (DT) fuel preparation, minimal hohlraum-plasma-mediated laser backscatter, low threshold-ignition temperatures ({approx_equal}4 keV) for relaxed hohlraum x-ray flux asymmetry tolerances, and minimal (two-) shock timing requirements. On the other hand, DS ignition presents several formidable challenges, encompassing room-temperature containment of high-pressure DT ({approx_equal}790 atm) in the inner shell, strict concentricity requirements on the two shells (<3 {mu}m), development of nanoporous (<100 nm cell size) low-density (<100 mg/cc) metallic foams for structural support of the inner shell and hydrodynamic instability mitigation, and effective control of hydrodynamic instabilities on the high-Atwood-number interface between the DT fuel and the high-Z inner shell. Recent progress in DS ignition designs and required materials science advances at the nanoscale are described herein. Two new ignition designs that use rugby-shaped vacuum hohlraums are presented that utilize either 1 or 2 MJ of laser energy at 3{omega}. The capability of the National Ignition Facility to generate the requested 2 MJ reverse-ramp pulse shapemore » for DS ignition is expected to be comparable to the planned high-contrast ({approx_equal}100) pulse shape at 1.8 MJ for the baseline cryogenic target. Nanocrystalline, high-strength, Au-Cu alloy inner shells are under development using electrochemical deposition over a glass mandrel, exhibiting tensile strengths well in excess of 790 atm. Novel, low-density (85 mg/cc) copper foams have recently been demonstrated using 10 mg/cc SiO{sub 2} nanoporous aerogels with suspended Cu particles. A prototype demonstration of an ignition DS is planned for 2008, incorporating the needed novel nanomaterials science developments and the required fabrication tolerances for a realistic ignition attempt after 2010.« less

Authors:
; ; ; ; ;  [1]
  1. Lawrence Livermore National Laboratory, University of California, Livermore, California 94551 (United States)
Publication Date:
OSTI Identifier:
20976616
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 14; Journal Issue: 5; Other Information: DOI: 10.1063/1.2716406; (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; COPPER; DENSITY; DEUTERIUM; ELECTRODEPOSITION; FOAMS; GELS; KEV RANGE 01-10; LASERS; NANOSTRUCTURES; PRESSURE RANGE MEGA PA 10-100; PULSE SHAPERS; SHELLS; SILICON OXIDES; TENSILE PROPERTIES; TRITIUM; US NATIONAL IGNITION FACILITY; X RADIATION

Citation Formats

Amendt, Peter, Cerjan, C., Hamza, A., Hinkel, D. E., Milovich, J. L., and Robey, H. F. Assessing the prospects for achieving double-shell ignition on the National Ignition Facility using vacuum hohlraums. United States: N. p., 2007. Web. doi:10.1063/1.2716406.
Amendt, Peter, Cerjan, C., Hamza, A., Hinkel, D. E., Milovich, J. L., & Robey, H. F. Assessing the prospects for achieving double-shell ignition on the National Ignition Facility using vacuum hohlraums. United States. doi:10.1063/1.2716406.
Amendt, Peter, Cerjan, C., Hamza, A., Hinkel, D. E., Milovich, J. L., and Robey, H. F. Tue . "Assessing the prospects for achieving double-shell ignition on the National Ignition Facility using vacuum hohlraums". United States. doi:10.1063/1.2716406.
@article{osti_20976616,
title = {Assessing the prospects for achieving double-shell ignition on the National Ignition Facility using vacuum hohlraums},
author = {Amendt, Peter and Cerjan, C. and Hamza, A. and Hinkel, D. E. and Milovich, J. L. and Robey, H. F.},
abstractNote = {The goal of demonstrating ignition on the National Ignition Facility [J. D. Lindl et al., Phys. Plasmas 11, 339 (2003)] has motivated a revisit of double-shell (DS) targets as a complementary path to the cryogenic baseline approach. Expected benefits of DS ignition targets include noncryogenic deuterium-tritium (DT) fuel preparation, minimal hohlraum-plasma-mediated laser backscatter, low threshold-ignition temperatures ({approx_equal}4 keV) for relaxed hohlraum x-ray flux asymmetry tolerances, and minimal (two-) shock timing requirements. On the other hand, DS ignition presents several formidable challenges, encompassing room-temperature containment of high-pressure DT ({approx_equal}790 atm) in the inner shell, strict concentricity requirements on the two shells (<3 {mu}m), development of nanoporous (<100 nm cell size) low-density (<100 mg/cc) metallic foams for structural support of the inner shell and hydrodynamic instability mitigation, and effective control of hydrodynamic instabilities on the high-Atwood-number interface between the DT fuel and the high-Z inner shell. Recent progress in DS ignition designs and required materials science advances at the nanoscale are described herein. Two new ignition designs that use rugby-shaped vacuum hohlraums are presented that utilize either 1 or 2 MJ of laser energy at 3{omega}. The capability of the National Ignition Facility to generate the requested 2 MJ reverse-ramp pulse shape for DS ignition is expected to be comparable to the planned high-contrast ({approx_equal}100) pulse shape at 1.8 MJ for the baseline cryogenic target. Nanocrystalline, high-strength, Au-Cu alloy inner shells are under development using electrochemical deposition over a glass mandrel, exhibiting tensile strengths well in excess of 790 atm. Novel, low-density (85 mg/cc) copper foams have recently been demonstrated using 10 mg/cc SiO{sub 2} nanoporous aerogels with suspended Cu particles. A prototype demonstration of an ignition DS is planned for 2008, incorporating the needed novel nanomaterials science developments and the required fabrication tolerances for a realistic ignition attempt after 2010.},
doi = {10.1063/1.2716406},
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}
}