Investigation of non-ideal effects in wave-heated dense microplasmas including multiply charged ions and excited species using particle-in-cell Monte Carlo-collision modeling*

In this work, we present a computational model for non-ideal plasma effects during the time evolution of a second-stage laser-heated discharge at high pressures.  The model extends a classical one-dimensional particle-in-cell Monte Carlo-collision (PIC-MCC) approach coupled with Maxwell’s equations for the laser-heating process of a xenon plasma.  Plasma non-ideality resulting from Coulomb coupling at high plasma densities is manifested as a depression in the effective ionization potential of atoms and the enhanced collision cross sections. We find that full ionization of the plasma is obtained on the picosecond time scale, starting from the skin layer and quickly expanding throughout the domain through an anomalous extension of the skin depth. More critically, we show that the inclusion of the non-ideal plasma effects results in more rapid ionization when compared to an ideal plasma, especially at higher pressures.  While the initial results in this work are obtained with a chemistry mechanism that includes singly charged ions only, the final work will consider multiply charged ions as well as excited species.  At higher pressures, higher charge states and excited states of xenon are expected to play an important role in the ionization process.