Comparison of Numerical and Experimental Near-Field Ion Velocity Distributions of the BHT-200-X3 Hall Thruster

Abstract

Near-field ion velocity distributions of a Busek BHT-200-X3 xenon Hall thruster obtained through numerical simulation are compared with laser-induced fluorescence measurements taken for one nominal operating condition. The numerical code Hybrid-PIC Hall, a 2D hybrid particle-in-cell model, is used to simulate an axisymmetric cross section of the plasma acceleration zone. A set of nine HPHall simulations are run using three dierent cathode positions and three dierent Bohm electron mobility coecients to study the eects of these parameters on ion acceleration. Six additional cases were run in an attempt to better match the simulation results to the experimental data. For model validation, agreement between the numerical and experimental results is examined. No simulations were able to simultaneously match both global operational parameters (i.e. thrust, discharge current, and beam current) and the ion velocity distributions measured in experiments. The shape of the axial velocity distributions can be closely matched by using high Bohm electron mobility values. However, this correlation comes at the expense of most probable ion velocity and discharge current agreement. Radial velocity distributions are more closely matched by the simulations, but the simulations uniformly predict lower than measured inward and higher than measured outward radial velocity components (relative to the centerline) from the annular acceleration channel.