Experimental and theoretical studies of

The Hall thruster is a mature electric propulsion device that holds considerable promise in terms of the propellant saving potential. However, the conventional annular design does not naturally scale to low power, leading to lower efficiency and aggravated lifetime issues. This study investigates cylindrical geometry Hall thrusters (CHTs) that have a lower surface-to-volume ratio, making them more promising for scaling down. A comprehensive experimental and theoretical analysis of CHT physics is conducted, addressing electron cross-field transport, propellant ionization, plasma-wall interaction, and the electron distribution function. Performance comparisons between large (600–1000 W) and miniaturized (50–300 W) CHTs indicate that they are comparable to state-of-the-art annular Hall thrusters of similar sizes. Noteworthy findings include unusually high ionization efficiency and enhanced electron transport. Kinetic simulations suggest strong fluctuation-enhanced electron diffusion and predict non-Maxwellian electron distribution shapes. The results offer insights into optimizing low-power space propulsion through flexible magnetic field configurations, which are pivotal for achieving high-efficiency operation.