Electric propulsion systems are a more mass efficient method for providing a change in velocity, ΔV, to on-orbit spacecraft, than their chemical counterparts. In comparison, electric systems generally have a much higher specific impulse, Isp, than chemical systems. One option within the realm of electric propulsion is Hall Effect Thrusters, which have moderately high specific impulse values. From their advent in the 1960s, Hall Effect Thrusters have been used for orbit station keeping, attitude control, and orbit transfer. Although the discharge cavity is conventionally circular, pseudo-linear or racetrack shaped cavities have been developed. Even though Hall thrusters have decades of flight heritage, there are still many plasma behavioral characteristics which are still unknown. Multiple non-intrusive measurement techniques were used to investigate plasma behavior both in the plume and in the channel of a pseudo linear Hall thruster. Through the visible emissions captured by a high-speed camera, breathing mode characteristics were induced and analyzed. Spoke structures were observed in only certain parts of the thruster channel. Additionally, the plume divergence was characterized by use of a Faraday probe along two axes of the thruster, indicating significantly different “keep out” regions for potential thruster use on spacecraft. Also, an irregularity was observed in the channel of the pseudo-linear thruster, which potentially could affect the lifespan of the thruster
