One-dimensional mixing model of ablative Rayleigh–Taylor instability in direct-drive implosion

Abstract A one-dimensional (1D) 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 (2024 arXiv: 2411.12392v2 ). 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 1D radiation hydrodynamics code and validated against two-dimensional planar simulations. The relative errors of the model for quantifying compression remain below 10%. 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.