One-dimensional static sheath characteristics

Abstract

The boundary layer between an electrode biased to a large negative potential (relative to the electron temperature eφ≫kTe ) and a collisionless argon plasma (n∼1×109 cm−3, kTe ∼2.5 eV) was studied using Langmuir probes. A simple model based on Child’s law, including finite electron temperature effects, was fit to data obtained from both cold and emitting probes. A convenient method was developed to locate the sheath edge using cold probes. The emitting probe experiments demonstrated what we believe is a new technique for measuring the potential within the non-neutral sheath region.