Title: Plasma kinetic effects on interfacial mix and burn rates in multispatial dimensions

Abstract

The physics of mixing in plasmas is of great significance to inertial confinement fusion and high energy density laboratory experiments. Two- and three-dimensional (2D and 3D) particle-in-cell simulations with a binary collision model are used to explore kinetic effects arising during the mixing of plasma media. The applicability of the one-dimensional (1D) ambipolarity condition is evaluated in 2D and 3D simulations of a plasma interface with a sinusoidal perturbation. The 1D ambipolarity condition is found to remain valid in 2D and 3D, as electrons and ions flow together required for $$J$$ = 0. Simulations of perturbed interfaces show that diffusion-induced total pressure imbalance and hydroflows flatten fine interface structures and drive rapid atomic mix. The atomic mix rate from a structured interface is faster than the ~$$\sqrt{\bar{t}}$$ scaling obtained from 1D theory in the small-Knudsen-number limit. Plasma kinetic effects inhibit the growth of the Rayleigh-Taylor instability at small wavelengths and result in a nonmonotonic growth rate scaling with wavenumber k with a maximum at a low k value, much different from $$\sqrt{Agk}$$ (where A is the Atwood number and g is the gravitational constant) as expected in the absence of plasma kinetic effects. Simulations under plasma conditions relevant to MARBLE separated-reactant experiments on Omega and the NIF show kinetic modification of DT fusion reaction rates. With non-Maxwellian distributions and relative drifts between D and T ions, DT reactivity is higher than that inferred from rates using stationary Maxwellian distributions. Reactivity is additionally revealed to be reduced in the presence of finite-Knudsen-layer losses.

Authors:

Yin, Lin  ^[1];

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• Search DOE PAGES for ORCID "0000-0002-8978-5320"
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Albright, Brian James  ^[1];

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• Search DOE PAGES for ORCID "0000-0002-7789-6525"
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Vold, Erik Lehman  ^[1];

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• Search DOE PAGES for ORCID "0000-0002-0434-990X"
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Nystrom, William David ^[1]; Bird, Robert Francis  ^[1];

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• Search DOE PAGES for ORCID "0000-0003-1228-498X"
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Bowers, Kevin J. ^[1]

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+ Show Author Affiliations

1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

Publication Date:

2019-06-17

Research Org.:

Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

Sponsoring Org.:

USDOE National Nuclear Security Administration (NNSA)

OSTI Identifier:

1544744

Report Number(s):

LA-UR-19-24145
Journal ID: ISSN 1070-664X

Grant/Contract Number:  

89233218CNA000001

Resource Type:

Accepted Manuscript

Journal Name:

Physics of Plasmas

Additional Journal Information:

Journal Volume: 26; Journal Issue: 6; Journal ID: ISSN 1070-664X

Publisher:

American Institute of Physics (AIP)

Country of Publication:

United States

Language:

English

Subject:

70 PLASMA PHYSICS AND FUSION TECHNOLOGY; 97 MATHEMATICS AND COMPUTING