Kinetic Structure of Multi-Ion Collisional Plasma Shocks and Its Implications for ICF Implosions*

Shock-driven ion-species stratification is a critically important effect for ICF-capsule implosions, resulting in the shock-front enrichment with the lighter ion species and the ICF-capsule-center enrichment with the heavier species upon the shock reflection. This imprint persists through the high-collisionality stagnation phase of a gas-filled OMEGA capsule implosion [1], influencing its yield. Yet, despite the apparent significance of shock structure, basic features of multi-ion plasma shocks remain poorly understood, inviting contradictory claims in the literature [cf., Ref. 2 and Ref. 3]. Using the new, multi-ion Vlasov-Fokker-Planck code iFP [4] developed at LANL, as well as direct comparisons to multi-ion hydrodynamic simulations and semi-analytical predictions, we disentangle the complicated structure of multi-ion plasma shocks, resolving along the way several controversies in the literature.

1. W. T. Taitano et al., Phys. Plasmas 25, 056310 (2018).
2. M. S. Greywall, Phys. Fluids 18, 1439 (1975).
3. C. Bellei et al., Phys. Plasmas 21, 056310 (2014).
4. W. T. Taitano et al., J. Comp. Phys. 297, 357 (2015); ibid. 318, 391 (2016); ibid. 339, 453 (2017); ibid. 365, 173 (2018).