Observation of persistent species temperature separation in inertial confinement fusion mixtures

Abstract

The injection and mixing of contaminant mass into the fuel in inertial confinement fusion (ICF) implosions is a primary factor preventing ignition. ICF experiments have recently achieved an alpha-heating regime, in which fusion self-heating is the dominant source of yield, by reducing the susceptibility of implosions to instabilities that inject this mass. We report the results of unique separated reactants implosion experiments studying pre-mixed contaminant as well as detailed high-resolution three-dimensional simulations that are in good agreement with experiments. At conditions relevant to mixing regions in high-yield implosions, we observe persistent chunks of contaminant that do not achieve thermal equilibrium with the fuel throughout the burn phase. The assumption of thermal equilibrium is made in nearly all computational ICF modeling and methods used to infer levels of contaminant from experiments. We estimate that these methods may underestimate the amount of contaminant by a factor of two or more.

Material Characterization of Hierarchical Tunable Pore Size Polymer Foams Used in the MARBLE Mix Morphology Experiment

“…As an example of this modeling, in Ref. 8,Haines et al summarize their results using highresolution 3-D simulations of as-built targets. 8 The MARBLE targets are requested with specific void sizes and percent void volumes.…”

“…8,Haines et al summarize their results using highresolution 3-D simulations of as-built targets. 8 The MARBLE targets are requested with specific void sizes and percent void volumes. Measurements taken on these targets include the target diameter, shell thickness, seam quality and width, void volume, and void size distribution within the foam.…”

“…Los Alamos National Laboratory has a customdesigned confocal micro-XRF instrument. Micro-XRF spectrometry [8][9][10][11][12][13][14][15] measures the emitted X-ray photons of a material excited by an X-ray source. Our system uses a Mo tube (25 W), with a pair of polycapillary optics, one on the source and the other on the detector.…”

Effect of Impurity Atoms on Thermonuclear Yield

“…The CR was varied from 12 to 20 by simply varying the temperature of the capsule that varied the vapor pressure and hence gas mass in the core [104][105][106]. Onedimensional xRAGE [5] simulations were able to match the increasing yield as the CR was increased with a yield-over-simulated (YOS) of better than 0.8.…”

“…The technique is being revived, however, as the Symcap platform is non-cryogenic and new, high-precision, high-energy spectrometers have become available at NIF. Non-spectroscopic techniques are also being employed to study this problem using nuclear diagnostics [5].…”