The Role of Magnetic Mirroring in Diverging Cusped Hall Thrusters

The development of efficient and long-lasting electric propulsion methods is a relevant area of research for the space industry and space exploration. A diverging cusped field hall thruster is a variant of a traditional hall thruster that utilizes diverging magnetic fields to increase the propellant utilization efficiency and life span for small thrusters. This increased efficiency and lifespan is due to magnetic mirroring. Magnetic mirroring is when an electron travels back and forth between two strong magnetic field strengths. On a scale with large amounts of electrons, they begin to localize in regions between the magnetic fields, which increases the ionization efficiency of the thruster. The magnetic fields also act as guidelines for moving electrons away from the walls of the discharge chamber, preventing erosion. The purpose of this research is to investigate how magnetic mirroring plays a role in electron movement and confinement when we change the divergence angle of the thruster. A design created by the Massachusetts Institute of Technology was used as a foundation for building an operational model but with variations in material choices. Simulations of nine different divergence angles were conducted in both axisymmetric Ansys Maxwell 2D to get magnetic field data from the permanent magnets and electric field data from our cathode and anode. With this data, we will run code in MATLAB to find important information that relates to electron confinement and movement such as magnetic mirroring ratio, E cross-B drifts, and escape angles. Once we know which divergence angle has the best characteristics the discharge chamber will be manufactured and tested to see what the performance characteristics are for the theoretical best divergence angle. This research project is designed to answer the question: How does magnetic mirroring affect electron movement and confinement in different divergent angles?