Magnetic nozzle design for coaxial plasma accelerators

Magnetic nozzles have great potential for improving the efficiency and performance of coaxial plasma accelerators in applications such as space propulsion and advanced manufacturing. Proper design of magnetic field geometry can improve coaxial accelerator performance in three ways. First, the applied field which intercepts the anode surface without directly connecting the two electrodes can minimize anode fall inefficiencies by improving electron conduction across the anode sheath and by opposing the Hall-induced starvation effect. Second, a properly designed magnetic geometry can provide a nozzling mechanism to permit the plasma to accelerate smoothly and efficiently from sub to super-magnetosonic flow. Third, a magnetic nozzle provides control over the flow of plasma from the accelerator. For applications such as surface modification and etching, magnetic nozzles can maximize the treatable surface area and tailor the downstream plasma energy distribution. For thrust generation, proper design of a magnetic nozzle can enable efficient detachment of the plasma from the magnetic field.>