The 8th International Conference on Matter and Radiation at Extremes (ICMRE2025)

23 / 2025-02-26 22:09:26

Large time-scale kinetic simulations of counter-propagating plasma shocks in the hohlraum

ion kinetic effects,shock wave interaction,ion mixing

The large time-scale evolution of two counter-propagating shock waves in a hohlraum has been investigated using hybrid fluid-PIC (particle-in-cell) simulations. This study explores the dynamics of shock wave evolution and the kinetic effects on the structure of colliding plasma shocks in complex multi-ion-species plasmas, with a particular focus on the expansion of high-Z plasma bubbles against the low-Z filled gas inside an inertial confinement fusion (ICF) hohlraum. The interacting shock waves along the axis generate a downstream wave-like electric field that reduces the kinetic energy of incoming particles and modulates ion density, forming a new high-temperature, high-density region. Upon reaching the hohlraum wall/gas interface, reflected shocks further compress and heat the gas plasma until dissipation. Additionally, the interaction between the shock waves and the interface leads to significant mixing of high-speed low-Z ions reflected by the shock waves with high-Z hohlraum wall plasma. Ultimately, the filled-gas plasma maintains a stable high-temperature, high-density state. However, over hundred-ps time scale, cumulative ion collisions can significantly alter the structure of the shock waves and the reflection of ions at the shock front. This study deepens the understanding of shock wave evolution in the hohlraum and contributes to improving the accuracy of plasma state predictions within the hohlraum.