Computational speed-up techniques for a PIC-MCC computer model for use in modeling the plasma in an ion engine discharge chamber

This paper presents the status of three techniques that have been studied for the purpose of reducing the computational time required by a fully coupled, particle tracking and electric field, PIC-MCC (particle-in-cell - Monte Carlo collision) computer model that simulates the plasma in the discharge chamber of an ion engine. The three techniques discussed in this paper are a particle fragmentation and merging technique, a semi-implicit multiple Poisson solves technique, and a semi-implicit fourth order electric field technique. While the particle fragmentation and merging technique successfully shows lower computational times, the semi-implicit techniques developed by the authors have not shown computational time improvements. The multiple Poisson solves technique does show increased stability over an explicit PIC-MCC technique for larger time step sizes.