Analysis of Multipactor Effects by a Particle-in-Cell Algorithm Integrated With Secondary Electron Emission Model on Irregular Grids

Abstract

We combine a novel finite-element-based electromagnetic particle-in-cell (EM-PIC) algorithm for the solution of Maxwell-Vlasov equations on irregular (unstructured) grids together with the Furman-Pivi probabilistic model governing the secondary electron emission process. The algorithm can be used for the analysis of resonant electron discharging phenomena (multipactor effects) in high-power radio frequency devices. In contrast to previous algorithms, the present EM-PIC algorithm yields a self-consistent time update of fields and particles on irregular grids with energy and charge conservation obtained from first principles. The use of unstructured grids enables local mesh refinement and simulation of complex geometries with minimal geometric defeaturing. We apply the algorithm to model multipactor effects on waveguides with flat or corrugated walls. We contrast the evolution of the electron population in various cases and investigate the respective saturation processes arising from self-field counterbalancing effects.