Multi-Megawatt MPD Plasma Source Operation and Modeling for Fusion Propulsion Simulations

Abstract

The expansion of a high temperature fusion plasma through an expanding magnetic field is a process common to most fusion propulsion concepts. The efficiency of this process has a strong bearing on the overall performance of fusion propulsion. In order to simulate the expansion of a fusion plasma, a concept has been developed in which a high velocity plasma is first stagnated in a converging magnetic field to high (100’s of eV) temperatures, then expanded though a converging/diverging magnetic nozzle. A Magnetoplasmadynamic (MPD) plasma accelerator has been constructed to generate the initial high velocity plasma and is currently undergoing characterization at the Ohio State University. The device has been operated with currents up to 300 kA and power levels up to 200 MWe. The source is powered by a 1.6 MJ, 1.6 ms pulse‐forming‐network. In addition to experimental tests of the accelerator, computational and theoretical modeling of both the accelerator and the plasma stagnation have been performed using the MACH2 MHD code. Insights into plasma compression and attachment to magnetic field lines have led to recommended design improvements in the facility and to preliminary predictions of nozzle performance.