Nonlinear Hybrid Boltzmann-PIC Acceleration Scheme

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), the ion plasma frequency ( 10), ion transit frequency ( 10), and the ionization frequency ( 10). To investigate long time scale, low frequency phenomenon 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 PIC ion source term. These approximations neglect e ects faster than ion time-scales, decreasing the computer time used by over an order of magnitude; however, they increase the complexity of the boundary conditions and the simulation is no longer self-consistent. This method is ideal for bounded systems in which the density is dynamic, and ambipolar di usion is important. Previous Boltzmann relation elds solves [1, 2, 3, 4, 5, 6, 7] did not evolve in time. This is accomplished enforcing charge and energy conservation with a modi ed MCC package based on work by Vahedi and Surendra[8]. The collision cross section, (E), can be a tabulated or tted function; the method is implemented with Xe and Ne cross sections. Theoretical rami cations 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 [9]) and two (XOOPIC [10, 11]) dimensions, emphasizing the temporal evolution of the breakdown.