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

S. C. Hsu; T. R. Joshi; P. Hakel; E. L. Vold; M. J. Schmitt; N. M. Hoffman; R. M. Rauenzahn; G. Kagan; X. -Z. Tang; R. C. Mancini; Y. Kim; H. W. Herrmann

doi:10.1209/0295-5075/115/65001

arXiv · 1606.06276

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

S. C. Hsu·T. R. Joshi·P. Hakel·E. L. Vold·M. J. Schmitt·N. M. Hoffman·R. M. Rauenzahn·G. Kagan·X. -Z. Tang·R. C. Mancini·Y. Kim·H. W. Herrmann

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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.

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S. C. Hsu, T. R. Joshi, P. Hakel, E. L. Vold, M. J. Schmitt, N. M. Hoffman, R. M. Rauenzahn, G. Kagan, X. -Z. Tang, R. C. Mancini, Y. Kim, H. W. Herrmann. 2016-06-20. Observation of interspecies ion separation in inertial-confinement-fusion implosions. https://doi.org/10.1209/0295-5075/115/65001

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