A one-dimensional mixing model for the impact of ablative Rayleigh-Taylor instability on compression dynamics

TL;DR

This paper develops a one-dimensional model to analyze how ablative Rayleigh-Taylor instability affects compression in laser-driven implosions, incorporating effects of initial perturbations and turbulence.

Contribution

It introduces a novel one-dimensional mixing model that integrates ablation effects, initial perturbations, and turbulence into radiation hydrodynamics simulations for better prediction of implosion dynamics.

Findings

Model accurately predicts implosion degradation due to mixing.

Mixing level correlates with the time between shock convergence and stagnation.

Model validated against two-dimensional simulations.

Abstract

A one-dimensional mixing model, incorporating the effects of laser ablation and initial perturbations, is developed to study the influence of ablative Rayleigh-Taylor instability on compression dynamics. The length of the mixing region is determined with the buoyancy-drag model[arXiv:2411.12392v2 (2024)]. The mixing effect on laser ablation is mainly described with an additional heat source which depends on turbulent kinetic energy and initial perturbation level through a free multiplier. The model is integrated into a one-dimensional radiation hydrodynamics code and validated against two-dimensional planar simulations. The further application of our model to spherical implosion simulations reveals that the model can give reasonable predictions of implosion degradation due to mixing, such as lowered shell compression, reduced stagnation pressure, and decreased areal density, etc. It is found that the time interval between the convergence of the main shock and stagnation may offer an estimate of mixing level in single-shot experiments.