The generation of plasma from hypervelocity impacts is an active research topic due to its important science and engineering ramifications in various applications. Previous studies have mainly focused on the ionization of the solid materials that constitute the projectile and the target. In this letter, we consider impact events that occur in a fluid (e.g., gas) medium, and present a multiphysics computational modeling approach and associated analysis to predict the behavior of the dynamic fluid–solid interaction that causes the surrounding fluid to ionize. The proposed computational framework is applied to a specific case involving a system of three interacting domains: a copper rod projectile impacting onto a soda lime glass target in a neon gas environment. The impact velocity is varied between $3\text{km}/\text{s}$ and $6\text{km}/\text{s}$ in different simulations. The computational model couples the compressible inviscid Navier–Stokes equations with the Saha ionization equations. The three material interfaces formed among the projectile, the target, and the ambient gas are tracked implicitly by solving two level set equations that share the same velocity field. The mass, momentum, and energy fluxes across the interfaces are computed using the FInite Volume method with Exact two-material Riemann problems (FIVER). The simulation result reveals a region of neon gas with high velocity, temperature, pressure, and mass density, formed in the early stage of the impact mainly due to the hypersonic compression of the fluid between the projectile and the target. For impact velocities higher than $4\text{km}/\text{s}$, ionization is predicted in this region.

超高速撞击产生等离子体是一个活跃的研究课题，因为它在各种应用中具有重要的科学和工程意义。以往的研究主要集中在构成弹丸和靶的固体材料的电离。在这封信中，我们考虑了流体（例如气体）介质中发生的撞击事件，并提出了一种多物理场计算建模方法和相关分析来预测导致周围流体电离的动态流体-固体相互作用的行为。所提出的计算框架应用于涉及三个相互作用域的系统的特定案例：铜棒射弹在氖气环境中撞击钠钙玻璃靶。冲击速度在$\mathrm{3个}\text{公里}/\text{秒}$和$\mathrm{6个}\text{公里}/\text{秒}$在不同的模拟中。该计算模型将可压缩无粘性 Navier-Stokes 方程与 Saha 电离方程耦合。通过求解共享相同速度场的两个水平集方程，隐式跟踪弹丸、目标和环境气体之间形成的三个材料界面。使用具有精确双材料黎曼问题 (FIVER) 的有限体积法计算界面上的质量、动量和能量通量。模拟结果揭示了在撞击早期形成的具有高速度、温度、压力和质量密度的氖气区域，主要是由于弹丸和目标之间的流体的高超音速压缩。对于高于$\mathrm{4个}\text{公里}/\text{秒}$，预计该区域会发生电离。