小行星撞击属于小概率但灾害链复杂的自然灾害，撞击伴随超高温、超高压、超高速等极端动力效应，会产生大量溅射粉尘。溅射粉尘被高速抛射进入大气层，部分粉尘进入平流层扩散，或引发全球性环境效应。开展撞击成坑—溅射粉尘全过程研究，对研究近地小行星防御与地球演化具有重要意义。目前，受技术和成本限制，室内超高速撞击试验难以开展真实工况模拟，数值模拟成为主要研究手段。但现有研究大多关注单一过程，缺少覆盖溅射粉尘形成—粉尘对流层运动—粉尘平流层扩散的完整链条的系统分析方法。
近日，中国科学院国家空间科学中心等采用多套数值模拟工具，完成小行星撞击成坑到粉尘全球扩散全链条仿真研究。研究采用有限元—光滑粒子流体动力学耦合方法，定量解析撞击成坑与溅射粉尘质量、动力学特征，发现溅射粉尘质量与小行星撞击能在双对数坐标系呈现良好线性关系；利用有限体积法揭示对流层内粉尘的四阶段演化过程；借助粒子扩散模型开展平流层长期模拟，揭示粉尘平流层扩散的时序层次性特征。模拟结果表明，小行星直径提升粉尘总产出，撞击速度提升粉尘向平流层输送比例。二者协同放大平流层粉尘载荷，巨型撞击留存的平流层粉尘对全球气候环境构成潜在威胁。
This research has established a complete numerical analysis framework covering impact cratering, atmospheric transport, and global diffusion, breaking through the previous limitations of only qualitative and single-link simulations, and can provide theoretical and technical support for disaster assessment of near-Earth asteroid defense.
The study pointed out that the current model has been partially simplified and has not fully considered complex processes such as thermal effects, phase changes, aerodynamics, etc. Further impact tests and numerical algorithms need to be developed in the future.
Relevant research results were published in "Science Bulletin" (Science Bulletin)superior.
小行星撞击地表灾害效应图
Distribution of dust volume fraction at different times (impact speed 10km/s, diameter 50m)
Source: https://www.cas.cn/syky/202609/t20260902_5119535.shtml