Numerical modeling of a pulsed electromagnetic plasma thruster experiment

We assessed the behavior and capabilities of a two-dimensional magnetohydrodynamic modeling code with a new tabular equation of state model for high-power pulsed plasma thrusters. The numerical results enabled detailed interpretation of the experimental data from a similar to 10-kJ pulsed coaxial plasma accelerator with ablative breech insulator pplytetrafluoroethylene. Our analysis showed that the initial conditions and ablation rate are critical to the behavior of the current sheet evolution in the numerical model. Qualitative agreement was obtained between the two-dimensional numerical model and experimental results, but there were significant quantitative discrepancies. The two-dimensional model indicates that some of the current remains trapped near the breech, because of the ablation of material off the breech boundary, Which appears to be supported by the experimental data. The sensitivity of the model to initial prefill density (small in comparison with the ablated mass) and ablation rate suggests that future modeling efforts involving high-power ablative fed pulsed plasma thrusters using the approach discussed in the paper should include a first-principles ablation model, together with density, temperature, and ablation rate estimates from the experimental apparatus.