Date of Award
2024
Document Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Mechanical and Aerospace Engineering
Committee Chair
Kunning G. Xu
Committee Member
Jason Cassibry
Committee Member
Robert A. Frederick
Committee Member
Samuel Langendorf
Committee Member
Wensheng Huang
Research Advisor
Kunning G. Xu
Subject(s)
Resonators, Plasma devices
Abstract
This work focuses on better understanding split-ring resonators (SRRs) as plasma devices and exploring their use as a plasma source in a two-stage Hall thruster. This is done by first studying the effect of a single versus a coupled SRR on plasma production. Through the use of simulations in ANSYS HFSS and Langmuir probe measurements, it is found that coupled SRRs result in a more uniform plasma at higher pressures due to the introduction of a secondary ionization point, and the electromagnetic coupling resulting in a slightly stronger electric field being produced at the primary gap. Experiments were also done on the effect of operating at the first versus second mode. Simulations in ANSYS HFSS showed a better reflection coefficient response for SRRs operating at the second mode. This also resulted in a higher peak electric field between the gap of the SRRs. Langmuir probe measurements were taken in argon at 95 mTorr to quantify the effect of this on the plasma properties. Four cases were studied including SRRs that had their outer rings as the powered rings that were operating at the first and second modes and SRRs that had the inner ring powered and operating at the first and second modes. It was found that operating at the second mode resulted in higher peak densities, but the overall average density of the system was largely unaffected. Then, magnetic field cusps were added to the system in order to observe if the magnetic cusps could increase electron density by reducing diffusion. Laser collisional induced fluorescence was used to measure the electron density and electron temperature. It was shown that the electrons did become magnetized, but the magnetic field resulted in a reduction of the electron density which was believed to be caused by the magnetic field affecting the electromagnetic resonance of the system. Finally, the SRR was placed in a Hall thruster and plume measurements were taken with a Faraday probe and a retarding potential analyzer. The thruster was found to produce thrusts up to 87 μN and Isp up to 45 s.
Recommended Citation
Walsten, Andrew, "Analysis of a magnetically enhanced microwave powered split-ring resonator plasma source for micropropulsion" (2024). Dissertations. 430.
https://louis.uah.edu/uah-dissertations/430