A Central-Cathode Electrostatic Thruster Featuring a High-Temperature Superconducting Applied Field Module

In recent decades, advances in electric propulsion have enabled the development of novel mission designs for space exploration. However, future deep space mission payloads of unprecedented mass will require advances in high thrust, high specific impulse propulsion. To achieve higher thrust density than traditional ion thrusters or Hall effect thrusters, novel designs for central-cathode electrostatic thrusters (CC-ESTs) and applied field magnetoplasmadynamic thrusters incorporate an applied magnetic field module which is used to accelerate plasma. The high thrust density of such designs makes them suitable candidates for further research and development for space deployment.

Crucial performance metrics of such thrusters have been shown to increase as the applied magnetic field increases, and high temperature superconducting (HTS) magnets show promise as low-power, high applied field modules. Both the strength and the profile of the applied magnetic field are closely tied to thruster performance. This raises the question- which magnetic fields improve thruster performance and why?

In this thesis, the impact of the magnetic field strength and profile on the performance of a plasma thruster is investigated. Numerical modelling of a central-cathode electrostatic thruster (CC-EST) was performed with particular regard to the detachment of plasma from magnetic field lines. This modelling was conducted alongside an experimental campaign to manufacture and integrate a high temperature superconducting applied field module with a CC-EST to characterise the HTS CC-EST performance. CC-EST performance was measured at central bore fields exceeding 1 T and with two different magnetic field profiles. These efforts have led to a novel understanding of the scaling of performance parameters in CC-EST with magnetic field, and how the performance of the thruster might be tailored to a specific application.