Effect of Macroparticle Weight Factor on Particle-in-Cell Simulations in Low Pressure Plasmas

Fully kinetic Particle-in-Cell/Monte Carlo Collisions (PIC/MCC) is an essential tool in understanding the complex physics of plasmas (CPP). Numerical accuracy and stability are important for PIC/MCC simulations and have been the subject of studies since its conception. Recent work reported that the plasma density of explicit electrostatic PIC/MCC simulations at steady state diverges with decreasing macroparticle weight for low pressure CCPs [1]. The simulations in [2] suggest around a thousand macroparticles per cell is required for convergence, indicating a high computational cost, especially in 2D or 3D cases. In this work, we revisited the macroparticle weight issue and explored the dependence of the plasma discharge properties on the particle weight. We will explore the numerical effects and physics regime related to this issue and its possible solutions.