Ph.D. Proposal

Julian Lopez-Uricoechea

(Professor Mitchell Walker)

Investigation of Anomalous Electron Phenomena in the Acceleration Region of a Hall Effect Thruster via Laser Thomson Scattering

Tuesday, October 15 

1 p.m. 

Daniel Guggenheim Building 244

Abstract 

Without experimental measurements to calibrate them, state-of-the-art Hall effect Thruster (HET) simulations are currently unable to accurately predict the performance or the life-limiting erosion rates of HETs. This inability is mainly attributed to the anomalous transport of electrons across magnetic field lines. As such, 1-D measurements of plasma properties across the acceleration region of a HET are routinely used to calibrate 2-D HET simulations for the axial profile of the electron Hall parameter. While these calibrated simulations can reproduce measured HET performance parameters, they do not reliably reproduce the measured life-limiting erosion rates or the electron temperature measurements made with laser Thomson scattering (LTS). To use 1-D measurements to calibrate 2-D simulations, simulations have used various unvalidated models for the variation of the electron Hall parameter along the magnetic field lines, and it is known that these different models predict significantly different erosion rates. The main goal of the proposed work is to noninvasively determine the 2-D map of the electron Hall parameter to accurately inform a model of the parallel-field variation of the electron Hall parameter in a HET. The proposed methodology is to use LTS to measure the 2-D map of the azimuthal electron drift velocity in a HET and to use these measurements to calibrate a HET simulation for the 2-D map of the electron Hall parameter. LTS simultaneously measures the electron temperature, so we will also combine our calibrated simulation to inform models for anomalous electron energy dynamics in a HET. By advancing the understanding of the underlying physics of HET operation, the proposed work could help the electric propulsion community develop a fully predictive HET simulation for the purpose of rapid optimization of HETs for operation at higher powers.

Committee

· Prof. Mitchell Walker – School of Aerospace Engineering (advisor)

· Prof. Sedina Tsikata – School of Aerospace Engineering

· Prof. Wenting Sun – School of Aerospace Engineering