Plasma Viscosity with Mass Transport in Spherical ICF Implosion Simulations

TL;DR

This paper investigates how plasma viscosity and atomic-level mixing influence inertial confinement fusion implosions, revealing significant effects on shock dynamics, temperature profiles, and neutron yields through advanced simulation modeling.

Contribution

The authors developed a one-dimensional spherical hydrodynamic code including plasma viscosity and mass transport, providing new insights into their effects on ICF implosion behavior.

Findings

Viscosity affects shock timing and temperature peaks.

Viscosity influences neutron production rates.

Viscosity reduces reliance on artificial numerical viscosity.

Abstract

The effects of viscosity and small-scale atomic-level mixing on plasmas in inertial confinement fusion (ICF) currently represent challenges in ICF research. Many current ICF hydrodynamic codes ignore the effects of viscosity though recent research indicates viscosity and mixing by classical transport processes may have a substantial impact on implosion dynamics. We have implemented a Lagrange hydrodynamic code in one-dimensional spherical geometry with plasma viscosity and mass transport and including a three temperature model for ions, electrons, and radiation treated in a gray radiation diffusion approximation. The code is used to study ICF implosion differences with and without plasma viscosity and to determine the impacts of viscosity on temperature histories and neutron yield. It was found that plasma viscosity has substantial impacts on ICF shock dynamics characterized by shock burn timing, maximum burn temperatures, convergence ratio, and time history of neutron production rates. Plasma viscosity reduces the need for artificial viscosity to maintain numerical stability in the Lagrange formulation and also modifies the flux-limiting needed for electron thermal conduction.