Numerical simulation of solid-density plasma dynamics driven by optical short pulse relativistic lasers and XFELs

The state-of-the-art optical short pulse relativistic lasers and X-ray free electron lasers (XFELs) with unprecedented light pressures enable to create the high-energy solid-density plasmas relevant to the interior of stars and planets, astrophysical jets and fusion devices. Yet, it is hardly accessible to fully probe the complex ultrafast plasma dynamics limited by the diagnostic spatial and temporal resolutions in experiments. Thus, the numerical simulations based on the particle-in-cell (PIC), magneto-hydrodynamics (MHD), molecular dynamics (MD), Vlasov-Fokker–Planck (VFP) and density-functional theory (DFT) provide the essential complementary capabilities to predict, explore and understand the fundamental plasma physics, with the aid of modern high performance computing clusters. In this talk, we will briefly introduce the algorithms of PIC code and implemented physics modules including binary collisions, non-equilibrium ionizations, and radiation transport in addition to the standard PIC cycle. Then we will give an overview of the PIC simulations of solid-density plasma dynamics driven by the optical short pulse relativistic lasers, with regard to the electron transport and secondary radiation, target heating and ionization, instabilities, and extreme electromagnetic fields generation. Lastly, we will present the numerical results to retrieve the temporal processes of XFEL-matter interactions with the newly implemented radiation transport model, for understanding the damaging mechanisms of the samples irradiated by an XFEL with intensity on the order of 1020 W/cm2 performed by our recent large-scale experiments.