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Session UI2: High Intensity Interactions and Advanced ICF Ignition

2:00 PM–5:00 PM, Thursday, November 1, 2012
Room: Ballroom DE

Chair: Natalia Krasheninnikova, Los Alamos National Laboratory

Abstract ID: BAPS.2012.DPP.UI2.5

Abstract: UI2.00005 : NIF Target Designs and OMEGA Experiments for Shock-Ignition Inertial Confinement Fusion

4:00 PM–4:30 PM

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Author:

K.S. Anderson
(Laboratory for Laser Energetics, U. of Rochester)

Shock ignition (SI)\footnote{R. Betti\textit{ et al.}, Phys. Rev. Lett. \textbf{98}, 155001 (2007).} is being pursued as a viable option to achieve ignition on the National Ignition Facility (NIF). Shock-ignition target designs require the addition of a high-intensity ($\sim $5 $\times $ 10$^{15}$ W/cm$^{2}$) laser spike at the end of a low-adiabat assembly pulse to launch a spherically convergent strong shock to ignite the imploding capsule. Achieving ignition with SI requires the laser spike to generate an ignitor shock with a launching pressure typically in excess of $\sim $300 Mbar. At the high laser intensities required during the spike pulse, stimulated Raman (SRS) and Brillouin scattering (SBS) could reflect a significant fraction of the incident light. In addition, SRS and the two-plasmon-decay instability can accelerate hot electrons into the shell and preheat the fuel. Since the high-power spike occurs at the end of the pulse when the areal density of the shell is several tens of mg/cm$^{2}$, shock-ignition fuel layers are shielded against hot electrons with energies below 150 keV. This paper will present data for a set of OMEGA experiments that were designed to study laser--plasma interactions during the spike pulse. In addition, these experiments were used to demonstrate that high-pressure shocks can be produced in long-scale-length plasmas with SI-relevant intensities. Within the constraints imposed by the hydrodynamics of strong shock generation and the laser--plasma instabilities, target designs for SI experiments on the NIF will be presented. Two-dimensional radiation--hydrodynamic simulations of SI target designs for the NIF predict ignition in the polar-drive beam configuration at sub-MJ laser energies. Design robustness to various 1-D effects and 2-D nonuniformities has been characterized. This work was supported by the U.S. Department of Energy Office of Inertial Confinement Fusion under Cooperative Agreement No. DE-FC52-08NA28302.

To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2012.DPP.UI2.5