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Title: Higher velocity, high-foot implosions on the National Ignition Facility laser

Abstract

By increasing the velocity in “high foot” implosions [Dittrich et al., Phys. Rev. Lett. 112, 055002 (2014); Park et al., Phys. Rev. Lett. 112, 055001 (2014); Hurricane et al., Nature 506, 343 (2014); Hurricane et al., Phys. Plasmas 21, 056314 (2014)] on the National Ignition Facility laser, we have nearly doubled the neutron yield and the hotspot pressure as compared to the implosions reported upon last year. The implosion velocity has been increased using a combination of the laser (higher power and energy), the hohlraum (depleted uranium wall material with higher opacity and lower specific heat than gold hohlraums), and the capsule (thinner capsules with less mass). We find that the neutron yield from these experiments scales systematically with a velocity-like parameter of the square root of the laser energy divided by the ablator mass. By connecting this parameter with the inferred implosion velocity (v), we find that for shots with primary yield >1 × 10{sup 15} neutrons, the total yield ∼ v{sup 9.4}. This increase is considerably faster than the expected dependence for implosions without alpha heating (∼v{sup 5.9}) and is additional evidence that these experiments have significant alpha heating.

Authors:
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  1. Lawrence Livermore National Laboratory, Livermore, CA 94551 (United States)
Publication Date:
OSTI Identifier:
22410410
Resource Type:
Journal Article
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 22; Journal Issue: 5; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1070-664X
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; CAPSULES; DEPLETED URANIUM; FIRST WALL; GOLD; IMPLOSIONS; LASER CAVITIES; LASERS; NEUTRONS; OPACITY; SPECIFIC HEAT; US NATIONAL IGNITION FACILITY; YIELDS

Citation Formats

Callahan, D. A., Hurricane, O. A., Hinkel, D. E., Döppner, T., Ma, T., Park, H.-S., Barrios Garcia, M. A., Berzak Hopkins, L. F., Casey, D. T., Cerjan, C. J., Dewald, E. L., Dittrich, T. R., Edwards, M. J., Haan, S. W., Hamza, A. V., Kritcher, A. L., Landen, O. L., LePape, S., MacPhee, A. G., Milovich, J. L., and and others. Higher velocity, high-foot implosions on the National Ignition Facility laser. United States: N. p., 2015. Web. doi:10.1063/1.4921144.
Callahan, D. A., Hurricane, O. A., Hinkel, D. E., Döppner, T., Ma, T., Park, H.-S., Barrios Garcia, M. A., Berzak Hopkins, L. F., Casey, D. T., Cerjan, C. J., Dewald, E. L., Dittrich, T. R., Edwards, M. J., Haan, S. W., Hamza, A. V., Kritcher, A. L., Landen, O. L., LePape, S., MacPhee, A. G., Milovich, J. L., & and others. Higher velocity, high-foot implosions on the National Ignition Facility laser. United States. doi:10.1063/1.4921144.
Callahan, D. A., Hurricane, O. A., Hinkel, D. E., Döppner, T., Ma, T., Park, H.-S., Barrios Garcia, M. A., Berzak Hopkins, L. F., Casey, D. T., Cerjan, C. J., Dewald, E. L., Dittrich, T. R., Edwards, M. J., Haan, S. W., Hamza, A. V., Kritcher, A. L., Landen, O. L., LePape, S., MacPhee, A. G., Milovich, J. L., and and others. Fri . "Higher velocity, high-foot implosions on the National Ignition Facility laser". United States. doi:10.1063/1.4921144.
@article{osti_22410410,
title = {Higher velocity, high-foot implosions on the National Ignition Facility laser},
author = {Callahan, D. A. and Hurricane, O. A. and Hinkel, D. E. and Döppner, T. and Ma, T. and Park, H.-S. and Barrios Garcia, M. A. and Berzak Hopkins, L. F. and Casey, D. T. and Cerjan, C. J. and Dewald, E. L. and Dittrich, T. R. and Edwards, M. J. and Haan, S. W. and Hamza, A. V. and Kritcher, A. L. and Landen, O. L. and LePape, S. and MacPhee, A. G. and Milovich, J. L. and and others},
abstractNote = {By increasing the velocity in “high foot” implosions [Dittrich et al., Phys. Rev. Lett. 112, 055002 (2014); Park et al., Phys. Rev. Lett. 112, 055001 (2014); Hurricane et al., Nature 506, 343 (2014); Hurricane et al., Phys. Plasmas 21, 056314 (2014)] on the National Ignition Facility laser, we have nearly doubled the neutron yield and the hotspot pressure as compared to the implosions reported upon last year. The implosion velocity has been increased using a combination of the laser (higher power and energy), the hohlraum (depleted uranium wall material with higher opacity and lower specific heat than gold hohlraums), and the capsule (thinner capsules with less mass). We find that the neutron yield from these experiments scales systematically with a velocity-like parameter of the square root of the laser energy divided by the ablator mass. By connecting this parameter with the inferred implosion velocity (v), we find that for shots with primary yield >1 × 10{sup 15} neutrons, the total yield ∼ v{sup 9.4}. This increase is considerably faster than the expected dependence for implosions without alpha heating (∼v{sup 5.9}) and is additional evidence that these experiments have significant alpha heating.},
doi = {10.1063/1.4921144},
journal = {Physics of Plasmas},
issn = {1070-664X},
number = 5,
volume = 22,
place = {United States},
year = {2015},
month = {5}
}