Ion kinetic effects in Richtmyer–Meshkov (RM) instability within high-energy-density plasmas lead to behavior distinct from that observed in conventional fluids. This study explores the influence of shock-driven, non-equilibrium energetic ions on RM instability evolution through hybrid fluid-particle-in-cell simulations. The results reveal that these energetic ions induce an anomalously diffusive mixing layer at the interface and preheat the material ahead of the shocks. Theoretical estimates for the widths of these anomalously diffusive mixing layers at the spike and bubble are proposed, demonstrating good agreement with simulation results and providing quantitative insight into the dynamics of interface mixing. Additionally, interface mixing driven by energetic ions can be modeled either as a reduction factor or as an enhanced viscosity, leading to suppression of the instability amplitude growth. These findings reveal that stronger shocks generate more energetic ions, enhancing anomalous diffusion and suppressing hydrodynamic instabilities. This underscores the importance of ion kinetic effects in RM instability behavior.
Lin et al. (Fri,) studied this question.