Numerical simulation of MPD thruster flows with anomalous transport

A fully two-dimensional, two-fluid numerical code has been specifically developed to study anomalous transport effects in an argon self-field coaxial MPD thruster. This model introduces several refinements to our previous work[1]. A finite volumes technique similar to that of Jameson[2] is used for the solution of the conservation equations, while concurrently solving the electromagnetic equations via a modified Jacobi method. This permits a faster and more accurate determination of spatial maps for the various steady-state flow and field properties to be computed. Also, in this paper, we extend the calculations to a range of typical operating conditions. The main goal is to compare the spatial distribution of these properties and the power dissipation in the thruster for simulation runs with and without anomalous transport. Anomalous transport theory takes into account the interaction between plasma waves and charged particles due to microinstabilities. A conductivity law based on the non-linear saturation of the lower hybrid current-driven instability[3] is used for the calculations. Comparisons with experimental performance show that anomalous effects may help the accuracy of fluid simulation of MPD thruster flows. Runs with anomalous transport for a geometry similar to the Full-scale Princeton Benchmark thruster (FSBT) revealed that the resistivity, in specific regions of the discharge (especially near the anode), is significantly higher than that calculated from classical runs. Dissipation was also enhanced and the thrust efficiency was adversely impacted by the microturbulence dropping by 13% at J²/m = 55 kA² sec/g.