Electron Density Characterization of a 2.45-GHz Microwave Electrothermal Thruster Plume Using Microwave Interferometry
Open Access
Author:
Ursic, Anze
Graduate Program:
Electrical Engineering
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
October 31, 2022
Committee Members:
Thomas F La Porta, Program Head/Chair Sven Bilen, Thesis Advisor/Co-Advisor Julio Urbina, Committee Member Jesse Kane Mc Ternan, Committee Member
Keywords:
Microwave Electrothermal Interferometry plasma plume thruster electron density
Abstract:
A microwave interferometry system for the nonintrusive characterization of microwave
electrothermal thruster plumes is described. The microwave electrothermal thruster
produces thrust by heating a propellant gas using microwave power and expelling it
through a nozzle. The microwave electrothermal thruster offers several advantages,
including longer lifetime due to the lack of electrode disintegration. This measurement
system is capable of determining the electron density by measuring with a vector network
analyzer the phase shift of a microwave signal transited through the plume. The phase
difference between vacuum and plasma is measured and used to determine electron
density.
This thesis presents experimental and computational research on this measurement
technique. Due to challenges in the collection of experimental data, an electron density
distribution was simulated and analyzed. The results show that the methodology
described in this thesis can be used to determine the general magnitude of electron
density of the plume. Thus, when usable phase data are collected in the future, the
provided MATLAB code can be used to determine the electron density distribution.
