We prefer the name constricted
plasma source because it more accurately captures the physics
of the discharge, which is strongly related to the formation
of an electron beam formed at a double layer at a physical
constriction between anode and cathode,8,14 rather than a
hollow shape of the anode. We will describe the construction
of the source, provide some basic plasma diagnostics of the
particles in the substrate region, and discuss the overall operational
principle.