Date of Award
2026
Document Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Mechanical and Aerospace Engineering
Committee Chair
Gabe Xu
Committee Member
Rob Adams
Committee Member
Jason Cassibry
Committee Member
Robert Frederick
Committee Member
Samuel Langendorf
Research Advisor
Gabe Xu
Subject(s)
Rockets (Aeronautics)--Nozzles, Plasma rockets
Abstract
A key part of any propulsion system is how the energy of the propellants is used for thrust. Because of the high temperatures of nuclear fusion plasma, traditional methods like guiding the propellant with walls are not feasible, so instead, electromagnetic forces must be used to avoid physical contact between the propellant and the vehicle. Usually, to do so the physical nozzle is replaced by a magnetic nozzle where the physical walls are replaced by magnetic fields. This thesis focuses on the direct imaging and probe measurements of a laser produced plasma expanding into a magnetic field as analogous event to the fusion reaction/magnetic nozzle interface. How these plasmas interacted with different magnetic fields in regard to expansion dynamics and stability was of the utmost importance. I tested the expansion of a plasma produced by the ablation of a solid target by a medium energy (400 mJ) laser into a multitude of field configurations. First, I used uniform magnetic fields created by the Magnetized Dusty Plasma Experiment (MDPX) over a wide range of conditions (0.125 T – 3 T) to understand how the plasma dynamics changed with increasing magnetic field. I found that the three regimes consisting of plasma pressure greater than magnetic pressure, plasma pressure equal to magnetic pressure, and plasma pressure less than magnetic pressure provided consistently different results. Additionally, the onset of electron-ion instability modes was confirmed in the high field regime. Next, I measured whether unique magnetic fields with positive curvature could enhance the stability of the expanding plasma. Using MDPX combined with a permanent magnet inserted into the bore, I was able to show that the confinement of the plasma was indeed increased as evidenced by the theory predicted bouncing behavior (up to 7 periods) and increased diamagnetic cavity lifetime (~ 1 μs). These results paint a clear path forward for the development of future flux compression magnetic nozzles by showing that high plasma pressure, plasma conductivity, and properly configured magnetic fields can increase vehicle performance by limiting losses.
Recommended Citation
White, Zachary K., "Investigation of a flux compression magnetic nozzle for pulsed plasma propulsion" (2026). Dissertations. 486.
https://louis.uah.edu/uah-dissertations/486