Observation of interspecies ion separation in inertial-confinement-fusion implosions

Abstract

We report direct experimental evidence of interspecies ion separation in direct-drive, inertial-confinement-fusion experiments on the OMEGA laser facility. These experiments, which used plastic capsules with D${}_2$/Ar gas fill (1% Ar by atom), were designed specifically to reveal interspecies ion separation by exploiting the predicted, strong ion thermo-diffusion between ion species of large mass and charge difference. Via detailed analyses of imaging x-ray-spectroscopy data, we extract Ar-atom-fraction radial profiles at different times, and observe both enhancement and depletion compared to the initial 1%-Ar gas fill. The experimental results are interpreted with radiation-hydrodynamic simulations that include recently implemented, first-principles models of interspecies ion diffusion. The experimentally inferred Ar-atom-fraction profiles agree reasonably, but not exactly, with calculated profiles associated with the incoming and rebounding first shock.

7 pages, 4 figures, 1 table; submitted for publication

References in corpus (7)

• The RAGE radiation-hydrodynamic code
• Electro-diffusion in a plasma with two ion species
• Thermo-diffusion in inertially confined plasmas
• Species separation and modification of neutron diagnostics in inertial-confinement fusion
• Plasma Viscosity with Mass Transport in Spherical ICF Implosion Simulations
• Direct asymmetry measurement of temperature and density spatial distributions in inertial confinement fusion plasmas from pinhole space-resolved spectra
• Plasma adiabatic lapse rate

Cited by in corpus (6)

• Laboratory Space Physics: Investigating the Physics of Space Plasmas in the Laboratory
• Observation and modeling of interspecies ion separation in inertial confinement fusion implosions via imaging x-ray spectroscopy
• Influence of coupling on thermal forces and dynamic friction in plasmas with multiple ion species
• Experimental Measurements of Ion Diffusion Coefficients and Heating in a Multi-Ion-Species Plasma Shock
• Observation of Shock-Front Separation in Multi-Ion-Species Collisional Plasma Shocks
• 2D Implosion Simulations with a Kinetic Particle Code