Automated calibration of the anomalous electron scattering frequency profile in one-dimensional Hall effect thruster simulations

To achieve agreement with experimental measurements, modeling of partially magnetized E×B plasmas typically requires the addition of a semi-empirical anomalous electron scattering frequency to enhance cross-field transport while using the drift-diffusion model for electrons. In the Hall effect thruster community, the state-of-the-art approach has relied on a combination of manual tuning of this profile and the use of Bohm-like crossfield diffusion terms. In this work, four gradient-based optimization algorithms—Adagrad, Adadelta, RMSProp, and Adam—are used to automatically calibrate the anomalous electron scattering frequency in a SPT-100 Hall effect thruster to reproduce ion laser induced fluorescence (LIF) measurements along the thruster centerline. While all methods tested showed comparable performance, the Adam algorithm appeared to be the most robust with large step sizes reducing the time needed for the optimization.