Drive Asymmetry and the Origin of Turbulence in an ICF Implosion

TL;DR

This study uses high-resolution 2D and 3D simulations to explore how drive asymmetry causes turbulence and mix in ICF implosions, highlighting a potential additional source of fuel mix affecting ignition.

Contribution

It reveals that long-wavelength drive asymmetries generate vortical structures that become turbulent in 3D, providing new insights into turbulence origin in ICF implosions.

Findings

Drive asymmetry leads to vortical structures in DT fuel.

3D instability of vortices causes turbulence and mix.

Implications for improving target ignition strategies.

Abstract

2D and 3D numerical simulations with the adaptive mesh refinement Eulerian radiation-hydrocode RAGE at unprecedented spatial resolution are used to investigate the connection between drive asymmetry and the generation of turbulence in the DT fuel in a simplified inertial-confinement fusion (ICF) implosion. Long-wavelength deviations from spherical symmetry in the pressure drive lead to the generation of coherent vortical structures in the DT gas and it is the three-dimensional instability of these structures that in turn leads to turbulence and mix. The simulations sug-gest that this mechanism may be an additional important source of mix in ICF implosions. Applications to target ignition at the National Ignition Facility are briefly discussed.