Simulation of laser preplasma interaction with ionization dynamics

Performance of laser-driven particle/radiation sources from solid targets is often impacted by the interaction of the laser with the preplasma generated by laser pedestal. The preplasma is usually ionized to a low charge state by the laser pedestal but it can be further ionized by the arrival of the main pulse, creating a different preplasma condition. We conducted particle-in-cell study of the effect of ionization dynamics in the preplasma using initial conditions from well-defined density profiles as well as those from the rad-hydro simulations of the pedestal target interaction. Spectrum and yield of the hot electrons generated are compared with the simulations assuming fixed charge state without ionization. The dynamics of the ionized electrons in the interaction is analyzed and will be discussed in the context of experiments aiming to optimize X-ray photon production.