Trans-Debye Scale Plasma Modeling & Stochastic GRB Wakefield Plasma   Processes
  Modeling plasma physical processes in astrophysical context demands for both detailed kinetics and large scale development of the electromagnetic field densities.   We present a new framework for modeling plasma physics of hot tenuous plasmas by a two-split scheme, in which the large scale fields are modeled by means of a particle-in-cell (PIC) code, and in which binary collision processes and single-particle processes are modeled through a Monte-Carlo approach. Our novel simulation tool -- the PhotonPlasma code -- is a unique hybrid model; it combines a highly parallelized (Vlasov) particle-in-cell approach with continuous weighting of particles and a sub-Debye Monte-Carlo binary particle interaction framework.   As an illustration of the capabilities we present results from a numerical study of Gamma-Ray Burst - Circumburst Medium interaction and plasma preconditioning via Compton scattering. We argue that important microphysical processes can only viably be investigated by means of hybrid codes such as the PhotonPlasma code.   Our first results from 3D simulations with this new simulation tool suggest that magnetic fields and plasma filaments are created in the wakefield of prompt gamma-ray bursts. Furthermore, the photon flux density gradient impacts on particle acceleration in the burst head and wakefield. We discuss some possible implications of the circumburst medium being preconditioned for a trailing afterglow shock front. We also discuss important improvements for future studies of GRB wakefields processes, using the PhotonPlasma code. 
J. Trier Frederiksen, T. Haugboelle, A. Nordlund