Generation of metal particle contaminants excited from ablated aluminum alloys by stray light

The ablation of aluminum alloy structural components by stray light during operation of the inertial confinement fusion (ICF) device results in the excitation of high-temperature, supersonic metal particulate contamination. However, previous research does not examine the mechanism by which metal particulate contaminants are generated during the ablation process. A three-phase (solid-liquid-gas) ablation model is developed employing the level set method (LSM) based on phase transition theory with improved Hertz-Langmuir functions to clarify the generation mechanism of metal particles. Comparing to the identical physical quantities considering the ambient pressure term of above ablation model, the maximum of the evaporation rate and plume velocity at the ablation zone calculated by previous oversimplified models are underestimated by ∼1380 kg m⁻² s⁻¹ and ∼450 m s⁻¹. The damage extent of the target is favorably characterized into four concentric banded areas extending to the ablated periphery by accounting for the thermal damage principle with proof-of-principle experiments. It is revealed that two typical metal particulate pollutants are generated during ablation process. The aggregated particles in the flow recast zone and the splash breakup zone are ejected due to the portion of the stagnation pressure of the melt exceeding the surface tension. The micro-/nanometer particulates distributed throughout the ablation zone are attributed to condensation of the vapor plumes and solidification of minute droplets. The research in this paper provides guidance for elucidating the influence of stray light laser on the capacity of the ICF device and effect of optical components precursor on laser-induced damage threshold (LIDT).