Kinetic Simulations of SPT and HEMP Thrusters Including the Near-Field Plume Region

The particle-in-cell (PIC) method is used to study two different ion thruster concepts-stationary plasma thrusters (SPTs) and high-efficiency multistage plasma thrusters (HEMP-Ts)-in particular, the plasma properties in the discharge chamber due to the different magnetic field configurations. Special attention is paid to the simulation of plasma particle fluxes on the thrusters' channel surfaces. In both cases, PIC proves itself as a powerful tool, delivering important insight into the basic physics of the different thruster concepts. The simulations demonstrated that the new HEMP-T concept allows for a high thermal efficiency due to both minimal energy dissipation and high acceleration efficiency. In the HEMP-T, the plasma contact to the wall is limited only to very small areas of the magnetic field cusps, which results in small ion energy flux to the thruster channel surface. The erosion yields for dielectric discharge channel walls of SPT and HEMP-Ts were calculated with the binary collision code SDTrimSP. For HEMP, thruster simulations have shown that there is no erosion inside the dielectric discharge channel.