Hybrid PIC acceleration schemes for discharges

Kinetic simulation of plasmas in which equilibrium occurs over ion timescales poses a computational challenge due to the disparate timescales of the electron plasma frequency ( ~10^9), the ion plasma frequency ( ~10^7), ion transit frequency ( ~10^6), and the ionization frequency ( ~10^7). A hybrid electrostatic PIC algorithm is presented in which the electrons reach thermodynamic equilibrium with the ions each time step, using the nonlinear Boltzmann relationship for the electrons with a source term. Collisions terms are computed using a Monte Carlo model in a fixed electric field; the rates are regenerated when the field changes by a prescribed fraction. These approximations decrease the computer time used by over an order of magnitude; however, they increase the complexity of the boundary conditions. Theoretical ramifications of these approximations are examined including comparisons with full PIC simulations of an AC plasma display panel (PDP). The PDP is a discharge in a Ne-Xe gas near atmospheric pressure. The comparison is done in both one (XPDP1 (Vahedi and Surendra, Comp. Phys. Com., 104 (1993))) and two (XOOPIC (Verboncoeur, et. al., Comp. Phys. Com., 87 (1995))) dimensions, emphasizing the temporal evolution of the breakdown.