Accurate modeling of the anomalous electron mobility is absolutely critical for successful simulation of Hall thrusters. In this work, existing computational models for the anomalous electron mobility are used to simulate the UM/AFRL P5 Hall thruster ͑a 5 kW laboratory model͒ in a two-dimensional axisymmetric hybrid particle-in-cell Monte Carlo collision code. Comparison to experimental results indicates that, while these computational models can be tuned to reproduce the correct thrust or discharge current, it is very difficult to match all integrated performance parameters ͑thrust, power, discharge current, etc.͒ simultaneously. Furthermore, multiple configurations of these computational models can produce reasonable integrated performance parameters. A semiempirical electron mobility profile is constructed from a combination of internal experimental data and modeling assumptions. This semiempirical electron mobility profile is used in the code and results in more accurate simulation of both the integrated performance parameters and the mean potential profile of the thruster. Results indicate that the anomalous electron mobility, while absolutely necessary in the near-field region, provides a substantially smaller contribution to the total electron mobility in the high Hall current region near the thruster exit plane.

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A data-driven approach to model calibration is developed to accurately obtain the input parameters for nonlinear dynamical systems. The paper focuses on the convergence properties of the proposed method, which play a significant role in understanding the validity and usefulness of any data-driven model. The input parameters of nonlinear dynamical systems are optimized to a reference solution, which can be experimental data or results from a high-fidelity computer simulation, using the Wasserstein metric and a phase-space representation of a set of time-dependent signals. Test cases shown in this paper include the Lorenz system and the discharge plasma of a Hall effect thruster to characterize the numerical uncertainties of the proposed data-driven approach, given a constructed reference solution. Distinct wells in the cost function, the Wasserstein metric, are obtained relative to the reference solution, illustrating the applicability of the proposed method to dynamical problems. The numerical uncertainties associated with the phase-space portrait and sampling time are discussed.

Accurate modeling of the anomalous electron mobility is crucial for successful simulation of Hall thrusters. Existing computational models for the anomalous electron mobility are used to simulate the UM/AFRL P5 Hall thruster in a 2D axisymmetric hybrid PIC-MCC code. Comparison to experimental results indicates that while these computational models can be tuned to reproduce the correct thrust or discharge current, it is very difficult to match all integrated performance parameters (thrust, power, discharge current, etc.) simultaneously. Furthermore, multiple configurations of these computational models can produce reasonable integrated performance parameters. Mean centerline potential profiles from these simulations are presented to provide physical insight into the relationship between the electron mobility and the spatial variation of the plasma potential.

A 2-D axisymmetric hybrid PIC-MCC model of the acceleration channel and near-field of dielectric wall-type Hall thrusters is tested on an SPT-100 type and a UM/AFRL P5 magnetic field configuration. The location of both the virtual cathode line (VCL) and virtual anode line (VAL) are varied on the SPT-100 type magnetic field configuration to study the model dependence on these parameters. A P5 simulation with and without doubly charged xenon is provided. For the particular SPT-100 type magnetic field configuration studied, there is a negligible dependence of performance parameters and plasma properties on the location of the VCL; however, the dependence on the location of the VAL is far more pronounced. Moving the VAL downstream results in decreased plasma density both in the acceleration channel and upstream of the VAL, diminished thruster performance parameters, and a lowering of the electron energy in the near-field region. Inclusion of Xe ++ led to little change in the performance characteristics of the thruster.