Title: Ion species stratification within strong shocks in two-ion plasmas

Abstract

We report strong collisional shocks in multi-ion plasmas are featured in many environments, with Inertial Confinement Fusion (ICF) experiments being one prominent example. Recent work [Keenan et al., Phys. Rev. E 96, 053203 (2017)] answered in detail a number of outstanding questions concerning the kinetic structure of steady-state, planar plasma shocks, e.g., the shock width scaling by the Mach number, M. However, it did not discuss shock-driven ion-species stratification (e.g., relative concentration modification and temperature separation). These are important effects since many recent ICF experiments have evaded explanation by standard, single-fluid, radiation-hydrodynamic (rad-hydro) numerical simulations, and shock-driven fuel stratification likely contributes to this discrepancy. Employing the state-of-the-art Vlasov-Fokker-Planck code, iFP, along with multi-ion hydro simulations and semi-analytics, we quantify the ion stratification by planar shocks with the arbitrary Mach number and the relative species concentration for two-ion plasmas in terms of ion mass and charge ratios. In particular, for strong shocks, we find that the structure of the ion temperature separation has a nearly universal character across ion mass and charge ratios. Lastly, we find that the shock fronts are enriched with the lighter ion species and the enrichment scales as M⁴ for M»1.

Authors:

Keenan, Brett D.  ^[1];

• Search DOE PAGES for author "Keenan, Brett D."
• Search DOE PAGES for ORCID "0000-0001-5722-5532"

Simakov, Andrei N.  ^[1];

• Search DOE PAGES for author "Simakov, Andrei N."
• Search DOE PAGES for ORCID "0000-0001-7064-9153"

Taitano, William T.  ^[1];

• Search DOE PAGES for author "Taitano, William T."
• Search DOE PAGES for ORCID "0000-0002-2369-0935"

Chacón, Luis  ^[1]

• Search DOE PAGES for author "Chacón, Luis"
• Search DOE PAGES for ORCID "0000-0002-4566-8763"

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+ Show Author Affiliations

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

Publication Date:

Thu Mar 01 00:00:00 EST 2018

Research Org.:

Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)

Sponsoring Org.:

USDOE National Nuclear Security Administration (NNSA); USDOE Laboratory Directed Research and Development (LDRD) Program

OSTI Identifier:

1427387

Alternate Identifier(s):

OSTI ID: 1423399

Report Number(s):

LA-UR-17-31485
Journal ID: ISSN 1070-664X; TRN: US1802459

Grant/Contract Number:  

AC52-06NA25396

Resource Type:

Accepted Manuscript

Journal Name:

Physics of Plasmas

Additional Journal Information:

Journal Volume: 25; Journal Issue: 3; 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