Effect of Anode Surface Conditions on Heaterless Hollow Cathode Performance

The study examines the effects of planar anode surface roughness on heaterless hollow cathode discharge characteristics. Three distinct roughness levels, Ra 1.6, Ra 3.2, and Ra 6.4, were achieved using a specialized machining procedure. A pivotal observation highlights the relationship between discharge voltage and the surface texture of the anode. As surface roughness intensifies, the planar anode demands a decreased discharge voltage to uphold the primary discharge. This phenomenon can be attributed to the increased surface area from roughness, promoting efficient electron current collection. Furthermore, oscillations in discharge voltage appear to be inversely proportional to the surface roughness of the planar anode, potentially tied to variations in the neutral gas density gradient near the anode and cathode. Such insights are instrumental for standardizing hollow cathode tests and set a foundation for more in-depth research in subsequent studies.