Coupled Fluid-Kinetic Numerical Method to Model Spacecraft Charging in LEO

Although spacecraft charging in low Earth orbit is generally regarded as insignificant because the cold dense ionospheric plasma prevents the development of strong potential differences, scientific satellites (e.g., Centre National d'Études Spatiales TARANIS satellite) carry very sensitive instruments, the measurements by which may be impacted by the charging of the spacecraft. In order to assess the effect of the spacecraft charging on the measurements, simulations will be performed using the Spacecraft Plasma Interaction System (SPIS) software. Different numerical schemes are implemented in the SPIS, but none is perfectly fit to perform very low-noise simulations for satellites in ionospheric plasma within an admissible computation time. In this paper, a coupling between the Poisson-Boltzmann approximation and the particle-in-cell schema is proposed. This results in having the advantages of the analytic methods in terms of statistical noise and computational resources without suffering from some of their limitations.