Magnetohydrodynamic Analysis of High-Density Plasma Hall Thruster Operation.

Abstract: Hall thrusters are widely used for efficient in-space propulsion, but their reliance on xenon presents challenges in terms of cost and availability. Alternative propellants such as argon or krypton exhibit lower propellant utilization efficiency, motivating thruster designs that increase plasma density within the ionization region. This work investigates such a scaling method using an analytical magnetohydrodynamic (MHD) framework to examine the effects of higher plasma density and magnetic field adjustments. Experimental Hall parameters and anomalous diffusion coefficients of existing thruster designs were estimated using the J × B force, highlighting differences between SPT and TAL configurations. A fluid-based MHD approach was then applied to identify the principal scaling parameters: mass flow density and magnetic flux density. The framework was demonstrated on the reference TAL-type thruster RAIJIN66. Reducing the anode cross-sectional area increased propellant utilization efficiency but also raised the discharge current and thermal load, which were mitigated by increasing the magnetic flux density. Importantly, while thrust remained essentially constant, the electron current was significantly reduced, illustrating the role of the magnetic field in controlling currents and thermal loads in high-density operation. These results highlight the importance of magnetic field adjustment in maintaining efficient thruster operation under high-density conditions and establish a first-order analytical tool for guiding the design of Hall thrusters using alternative propellants, with potential applications to future high-density, ion-magnetized regimes.

Recommended citation: Barth, N., Komurasaki, K., Satpathy, D., Lee, J., Sekine, H., & Koizumi, H. Magnetohydrodynamic Analysis of High-Density Plasma Hall Thruster Operation. In 39th International Electric Propulsion Conference, Imperial College London, London, United Kingdom. 2025, September.
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