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Title: Inferring fuel areal density from secondary neutron yields in laser-driven magnetized liner inertial fusion

Abstract

A technique to infer the areal density ρR of compressed deuterium (D) in cylindrical implosions from the ratio of secondary D–T (deuterium–tritium) neutrons to primary D–D neutrons is described and evaluated. For ρR to be proportional to the ratio of D–T to D–D yield, the increase in the D–T fusion cross section with collisional slowing of the tritium must be small, requiring where TkeV is the electron temperature in keV. The technique is applied to results from laser-driven magnetized liner inertial fusion (MagLIF) targets on OMEGA, where ρR is certainly less than 4 mg/cm 2. OMEGA MagLIF targets do not achieve a sufficiently high, radially integrated, axial magnetic field BR to confine the tritium, as occurs in Z MagLIF targets, because they are ~10× smaller in radius. The inferred areal densities show that fuel convergence is reduced by preheating, by an applied axial magnetic field, and by increasing the initial fuel density, which are key features of the MagLIF scheme. The results are compared with 1-D and 2-D magnetohydrodynamic simulations for nominal laser and target parameters, which predict areal densities 2× to 3× higher than the measurements.

Authors:
 [1]; ORCiD logo [1];  [1];  [1];  [1];  [1];  [1]; ORCiD logo [1];  [1]
  1. Univ. of Rochester, NY (United States). Lab. for Laser Energetics
Publication Date:
Research Org.:
Laboratory for Laser Energetics, University of Rochester
Sponsoring Org.:
USDOE Advanced Research Projects Agency - Energy (ARPA-E)
Contributing Org.:
Laboratory for Laser Energetics, University of Rochester
OSTI Identifier:
1498079
Report Number(s):
2018-304, 1490, 2429
Journal ID: ISSN 1070-664X; 2018-304, 1470, 2429
Grant/Contract Number:  
NA0003856
Resource Type:
Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 26; Journal Issue: 2; Journal ID: ISSN 1070-664X
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English

Citation Formats

Davies, J. R., Barnak, D. H., Betti, R., Campbell, E. M., Glebov, V. Yu., Hansen, E. C., Knauer, J. P., Peebles, J. L., and Sefkow, A. B. Inferring fuel areal density from secondary neutron yields in laser-driven magnetized liner inertial fusion. United States: N. p., 2019. Web. doi:10.1063/1.5082960.
Davies, J. R., Barnak, D. H., Betti, R., Campbell, E. M., Glebov, V. Yu., Hansen, E. C., Knauer, J. P., Peebles, J. L., & Sefkow, A. B. Inferring fuel areal density from secondary neutron yields in laser-driven magnetized liner inertial fusion. United States. doi:10.1063/1.5082960.
Davies, J. R., Barnak, D. H., Betti, R., Campbell, E. M., Glebov, V. Yu., Hansen, E. C., Knauer, J. P., Peebles, J. L., and Sefkow, A. B. Mon . "Inferring fuel areal density from secondary neutron yields in laser-driven magnetized liner inertial fusion". United States. doi:10.1063/1.5082960.
@article{osti_1498079,
title = {Inferring fuel areal density from secondary neutron yields in laser-driven magnetized liner inertial fusion},
author = {Davies, J. R. and Barnak, D. H. and Betti, R. and Campbell, E. M. and Glebov, V. Yu. and Hansen, E. C. and Knauer, J. P. and Peebles, J. L. and Sefkow, A. B.},
abstractNote = {A technique to infer the areal density ρR of compressed deuterium (D) in cylindrical implosions from the ratio of secondary D–T (deuterium–tritium) neutrons to primary D–D neutrons is described and evaluated. For ρR to be proportional to the ratio of D–T to D–D yield, the increase in the D–T fusion cross section with collisional slowing of the tritium must be small, requiring where TkeV is the electron temperature in keV. The technique is applied to results from laser-driven magnetized liner inertial fusion (MagLIF) targets on OMEGA, where ρR is certainly less than 4 mg/cm2. OMEGA MagLIF targets do not achieve a sufficiently high, radially integrated, axial magnetic field BR to confine the tritium, as occurs in Z MagLIF targets, because they are ~10× smaller in radius. The inferred areal densities show that fuel convergence is reduced by preheating, by an applied axial magnetic field, and by increasing the initial fuel density, which are key features of the MagLIF scheme. The results are compared with 1-D and 2-D magnetohydrodynamic simulations for nominal laser and target parameters, which predict areal densities 2× to 3× higher than the measurements.},
doi = {10.1063/1.5082960},
journal = {Physics of Plasmas},
number = 2,
volume = 26,
place = {United States},
year = {2019},
month = {2}
}

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