Optimal Experimental Design for Inferring Anomalous Electron Transport Coefficients in a Hall Thruster Model

Due to the potential of Hall thrusters for deep space propulsion applications, improvement in predictive models for the operation of these devices at flight conditions has increased in importance. One of the key concepts prohibiting the progression of these models due to the current limited understanding is the cross-field electron movement known as anomalous electron transport. The current method of approaching this problem is to tune transport model coefficients to data, such as ion velocity measurements. One problem introduced with this method is the large datasets necessary for calibration and the cost of obtaining or measuring these datasets. A solution is to apply an Optimal Experimental Design(OED). OED provides a rigorous framework for identifying conditions for the facility, thruster, or probes, for example, to conduct experiments that most improves the model calibration. In this work, a batching OED algorithm is developed and applied to iterate over sets of optimal conditions for ion velocity data that calibrate a multi-fluid Hall thruster model with incorporated anomalous transport closure models for collision frequency. As a result, it is shown that the same coefficient values can be achieved with a fraction of the typical number of experimental points that are employed. This work demonstrates an efficient approach for future Hall thruster testing that reduces the cost generated by a relatively expensive form of measurement, Laser Induced Fluorescence.