Comparison of Simulated Plasma Flowfields to Experimental Measurements for a Gas-Fed Magnetoplasmadynamic Thruster

The flowfield of a magnetoplasmadynamic thruster was simulated numerically and the results compared to experimental measurements, in order to validate the code and obtain insight into underlying physical processes. The thruster chosen was the full-scale benchmark thruster, because it has been the subject of many experimental studies. The parallelized axi-symmetric code featured detailed physical models and a finite volume formulation that allowed for non-orthogonal grids. Flowfield properties, such as electron density, velocity, current density, electron temperature, ionization fraction, mass and momentum flux, as well as thrust, compared favorably with existing data. The simulation provided insight into some aspects of thruster operation, such as the weak role of the anode geometry in affecting the thrust, the predominantly electromagnetic nature of the thrust at nominal operating conditions, and the importance of the near cathode region in energy dissipation. Nomenclature ρ Total mass density u Fluid velocity B Magnetic induction p, p̄ Gas pressure, isotropic pressure tensor E Electric field strength E′ Electric field seen by the plasma E Energy density of the plasma j Current per unit area kB Boltzmann’s constant ke,i Electron/ion thermal conduction coefficient me Mass of an electron ph, pe Heavy species/electron pressure Th, Te Heavy species/electron temperature η Resistivity