Numerical thermalization time scaling of 2D electromagnetic collisional plasmas

Summary form only given. Numerical thermalization is a numerical artifact in Particle-In-Cell (PIC) simulations which cannot be ignored as the transition of the velocity distribution towards a Maxwellian type varies with the number of particles per Debye length for collisionless plasma1. It has been recently identified that the thermalization time is greatly reduced with the inclusion of collisions for one-dimensional (1D) electrostatic collisional plasmas2. For 1D collisional plasma, the thermalization time scales with Nd (ν0/ωpe)-1, where ND is the number of particles per Debye length, υ0 is the collision frequency and ωpe is the plasma frequency.Thus, it is of interest to plot the scaling for a 2D collisional plasma and illustrate the dependence of thermalization time with respect to ND and u0/wpe. In addition, our simulation results demonstrate that the thermalization time is proportional to 1/ND for very small u0/wpe (similar to the 2D collisionless case3) as a vote of confidence in our in-house developed electromagnetic PIC code (IPIC). A comparison of the 2D and 1D scalings as a function of ND and u0/wpe will be discussed.