Self consistent kinetic simulations of SPT and HEMP thrusters including the near-field plume region

TL;DR

This study uses Particle-in-Cell simulations to compare SPT and HEMP ion thrusters, revealing that HEMP offers higher efficiency and less channel erosion due to its magnetic field configuration.

Contribution

First comprehensive kinetic simulation of both SPT and HEMP thrusters including near-field plume analysis, highlighting differences in plasma-wall interactions and erosion.

Findings

HEMP thrusters have minimal wall erosion compared to SPT.

HEMP achieves higher thermal efficiency due to limited plasma contact with walls.

Simulations show significant differences in plasma properties and erosion between the two thruster types.

Abstract

The Particle-in-Cell (PIC) method was used to study two different ion thruster concepts - Stationary Plasma Thrusters (SPT) and High Efficiency Multistage Plasma Thrusters (HEMP-T), in particular the plasma properties in the discharge chamber due to the different magnetic field configurations. Special attention was paid to the simulation of plasma particle fluxes on the thrusters channel surfaces. In both cases, PIC proved itself as a powerful tool, delivering important insight into the basic physics of the different thruster concepts. The simulations demonstrated that the new HEMP thruster concept allows for a high thermal efficiency due to both minimal energy dissipation and high acceleration efficiency. In the HEMP thruster the plasma contact to the wall is limited only to very small areas of the magnetic field cusps, which results in much smaller ion energy flux to the thruster channel surface as compared to SPT. The erosion yields for dielectric discharge channel walls of SPT and HEMP thrusters were calculated with the binary collision code SDTrimSP. For SPT, an erosion rate on the level of 1 mm of sputtered material per hour was observed. For HEMP, thruster simulations have shown that there is no erosion inside the dielectric discharge channel.