Modelling Novel Linear Parabolic Magnetic Nozzle Configurations for a Z-Pinch Fusion Propulsion System

One of the major obstacles to efficient interplanetary or interstellar travel is the long timeframes required to reach distant destinations using current chemical or electrical propulsion technology. Fusion propulsion could accelerate travel to Mars due to its high specific impulse and moderate thrust, which is not available using traditional chemical or electric propulsion systems. Pulsed fusion systems, which release short high-intensity bursts of power rather than sustained operation, have increasingly grown popular amongst various startups and government laboratories as they require simpler reactor designs, face less severe thermal environments, and limit instability growth through the brief confinement times from pulsed operation. Z-pinch, a pulsed form of magneto-inertial fusion (MIF), features a plasma that is compressed to ignition/fusion conditions by its own self-generated magnetic fields by running a high current through it. Nozzle geometry and its effects on an engine's performance have been investigated for multiple types of fusion-based propulsion, but this component has not yet been studied for systems that take advantage of the inherent cylindrical symmetry of a plasma produced via z-pinch. This study investigates the novel idea of orienting a pinch sideways in a linear parabolic nozzle to evaluate its viability for space propulsion. Several plasma initial temperatures are simulated and the effects on specific impulse and impulse bit are analyzed for an Ammonia propellant. Additionally, steps moving forward to analyze the performance of a magnetic coil design suited for this cylindrical symmetry are put forth. The goal is to identify magnetic fields that maximize specific impulse and impulse bit. By optimizing these figures of merit, necessary spacecraft mass and mission duration could potentially be reduced for interplanetary travel.