Wetted Foam Liquid DT Layer ICF Experiments at the NIF
ORAL
Abstract
A key physics issue in indirect-drive ICF relates to the understanding of the limitations on hot spot convergence ratio (CR), principally set by the hohlraum drive symmetry, the capsule mounting hardware (the ``tent''), and the capsule fill tube. An additional key physics issue relates to the complex process by which a hot spot must be dynamically formed from the inner ice surface in a DT ice-layer implosion. These physics issues have helped to motivate the development of a new liquid DT layer wetted foam platform$^{\mathrm{1}}$ at the NIF that provides an ability to form the hot spot from DT vapor and experimentally study and understand hot spot formation at a variety of CR's in the range of 12\textless CR\textless 25. Flexibility in CR will provide a means for exploring variations in the partitioning of available energy between the hot spot and the low adiabat cold fuel during the stagnation process and can allow for a fundamentally different (and potentially more robust) process of hot spot formation$^{\mathrm{2}}$. This new experimental platform is currently being used in a series of experiments to discover a range of CR's at which DT layered implosions will have understandable performance -- providing a sound basis from which to determine the requirements for ICF ignition. $^{\mathrm{1}}$R. E. Olson \textit{et al}., J. Phys. Conf. Ser. \textbf{717}, 012042 (2016). $^{\mathrm{2}}$R. E. Olson and R. J. Leeper, Phys. Plasmas \textbf{20}, 092705 (2013).
*This work was performed under the auspices of the U. S. DOE by LANL under contract DE-AC52-06NA25396
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