A 2D3V PIC-MCC model for simulating electrostatic discharging on charged spacecraft under high power microwave

Abstract Spacecraft are required to operate long-term in the complex space environment, where their surfaces can be charged due to effects with energetic particles. Under such conditions, the high-power microwave (HPM) electromagnetic fields are more likely to trigger discharge on spacecraft. To investigate the surface flashover mechanism of dielectric materials under the hybrid influence of HPM and surface electrostatic field, we conducted a numerical study employing a 2D3V (two-dimensional spatial and three-dimensional velocity) distribution model, which based on the particle-in-cell-Monte Carlo collision. The simulation incorporates key physical processes, including field electron emission, secondary electron multiplication, surface charge accumulation, and gas collision ionization. Furthermore, the effects of various parameters on electrostatic discharge behavior are systematically analyzed. An adaptive mesh refinement method is employed to ensure high computational accuracy without significantly increasing simulation time. Notably, when the surface is pre-charged, after secondary electron multiplication reaches saturation, the number of electrons in the surrounding space and related dynamic behaviors exhibit stable oscillations synchronized with the microwave frequency. As gas ionization progresses, a plasma sheath gradually forms near the surface. Additionally, the simulation also explores the influence of different factors on discharge. This study contributes to a more comprehensive understanding of the surface flashover process in pre-charged dielectric materials exposed to HPM radiation.