Simulation of the expansion within a vacuum chamber of the plume of a Hall thruster with a centrally mounted cathode

The simulation of a Hall effect thruster and its plume interaction with the spacecraft and ground facilities is of great importance for the design and development phases. In the frame of H2020 ASPIRE project (Advanced Space Propulsion for Innovative Realization of Space Exploration), several studies are going to be conducted in order to assess the role of vacuum chamber back-pressure, chamber walls and electric circuit behavior. In the frame of the project PROMETEO and in order to model the involved physics, an in-house 3D hybrid PICfluid code, called EP2PLUS [1], has been upgraded. It features an equivalent electric circuit solver employing a simplified sheath model, several surface properties for plasma-object interaction, and a nonlinear Poisson's equation solver to better characterize non-neutral plasma regions especially near the side and rear metallic walls of the thruster assembly. The magnetized electrons are treated as a polytropic fluid subject to both collisions and magnetic field effects, and the heavy species are simulated as macro-particles of a particle-in-cell model. The output of this demonstration study is a simplified but still self-consistent simulation of an HET plume expansion in a vacuum chamber scenario. An assessment of stray currents in the Direct Drive "grounded CRP" strategy [2] complements the results.