The experimental plan for cryogenic layered target implosions on the National Ignition Facility—The inertial confinement approach to fusion

Journal Article · Wed Jun 01 00:00:00 EDT 2011 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.3592173· OSTI ID:1959457

Edwards, M. J.; Lindl, J. D.; Spears, B. K.; Weber, S. V.; Atherton, L. J.; Bleuel, D. L.; Bradley, D. K.; Callahan, D. A.; Cerjan, C. J.; Clark, D.; Collins, G. W.; Fair, J. E.; Fortner, R. J.; Glenzer, S. H.; Haan, S. W.; Hammel, B. A.; Hamza, A. V.; Hatchett, S. P.; Izumi, N.; Jacoby, B. ; Jones, O. S.; Koch, J. A.; Kozioziemski, B. J.; Landen, O. L.; Lerche, R.; MacGowan, B. J.; MacKinnon, A. J.; Mapoles, E. R.; Marinak, M. M.; Moran, M.; Moses, E. I.; Munro, D. H.; Schneider, D. H.; Sepke, S. M.; Shaughnessy, D. A.; Springer, P. T.; Tommasini, R.; Bernstein, L.; Stoeffl, W.; Betti, R.; Boehly, T. R.; Sangster, T. C.; Glebov, V. Yu.; McKenty, P. W.; Regan, S. P.; Edgell, D. H.; Knauer, J. P.; Stoeckl, C.; Harding, D. R.; Batha, S.; Grim, G.; Herrmann, H. W.; Kyrala, G.; Wilke, M.; Wilson, D. C.; Frenje, J.; Petrasso, R.; Moreno, K.; Huang, H.; Chen, K. C.; Giraldez, E.; Kilkenny, J. D.; Mauldin, M.; Hein, N.; Hoppe, M.; Nikroo, A.; Leeper, R. J.

Ignition requires precisely controlled, high convergence implosions to assemble a dense shell of deuterium-tritium (DT) fuel with ρR>~1 g/cm² surrounding a 10 keV hot spot with ρR ~ 0.3 g/cm². A working definition of ignition has been a yield of ~1 MJ. At this yield the α-particle energy deposited in the fuel would have been ~200 kJ, which is already ~10 × more than the kinetic energy of a typical implosion. The National Ignition Campaign includes low yield implosions with dudded fuel layers to study and optimize the hydrodynamic assembly of the fuel in a diagnostics rich environment. The fuel is a mixture of tritium-hydrogen-deuterium (THD) with a density equivalent to DT. The fraction of D can be adjusted to control the neutron yield. Yields of ~10^14-15 14 MeV (primary) neutrons are adequate to diagnose the hot spot as well as the dense fuel properties via down scattering of the primary neutrons. X-ray imaging diagnostics can function in this low yield environment providing additional information about the assembled fuel either by imaging the photons emitted by the hot central plasma, or by active probing of the dense shell by a separate high energy short pulse flash. The planned use of these targets and diagnostics to assess and optimize the assembly of the fuel and how this relates to the predicted performance of DT targets is described. It is found that a good predictor of DT target performance is the THD measurable parameter, Experimental Ignition Threshold Factor, ITFX ~ Y × dsf ^2.3, where Y is the measured neutron yield between 13 and 15 MeV, and dsf is the down scattered neutron fraction defined as the ratio of neutrons between 10 and 12 MeV and those between 13 and 15 MeV.

• Research Organization: Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Los Alamos National Laboratory (LANL), Los Alamos, NM (United States); Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA)
• Grant/Contract Number: AC52-07NA27344
• OSTI ID: 1959457
• Alternate ID(s): OSTI ID: 21537782; OSTI ID: 1959495
• Report Number(s): LLNL-JRNL-433484; 397281
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 5 Vol. 18; ISSN 1070-664X
• Publisher: American Institute of Physics (AIP)
• Country of Publication: United States
• Language: English