Development and experimental characterization of a wall-less Hall thruster

An alternative Hall thruster architecture that shifts the ionization and acceleration regions outside the plasma chamber is demonstrated. This unconventional design is here termed a “wall-less Hall thruster,” as the bulk of the magnetized discharge is no longer limited by solid boundaries. A 200 W prototype with permanent magnets has been developed and characterized. Experimental results concerning the thruster operation, discharge oscillations, electric field distribution, and ionization zone characteristics are presented and discussed. Our first experiments show that the cross-field discharge can be moved outside the cavity without drastically disturbing the ion production and acceleration mechanisms. This design offers the benefit of reduced plasma-wall interaction and lower wall losses, while also greatly facilitating diagnostic access to the entire discharge ionization and acceleration regions.