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

doi:10.1063/1.5082960

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

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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:

Davies, J. R. ^[1];

^[1]; Betti, R. ^[1]; Campbell, E. M. ^[1]; Glebov, V. Yu. ^[1]; Hansen, E. C. ^[1]; Knauer, J. P. ^[1];

^[1]; Sefkow, A. B. ^[1]

Univ. of Rochester, NY (United States). Lab. for Laser Energetics

Publication Date:: 2019-02-11

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.

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                    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.

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                    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.

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@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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