Electric fields in a sheath near discontinuous surfaces

Summary form only given. Spatially resolved electric fields in an argon sheath region near discontinuous surfaces are measured using laser-induced fluorescence-dip spectroscopy (LIF-dip). The fields were determined by observing experimentally determined Stark-shifted transitions to the 13d[3/2]/sub 1/ Rydberg state. Surface discontinuities included metal-dielectric, metal-metal and metal-step junctions. Spatial maps of electric fields, as well as spatial maps of metastable populations, optical emission and ion density are obtained in the regions near these discontinuities as a function of power and pressure of the discharge. These measurements indicate that the presence of these discontinuities induce spatial non-uniformities across the surface. The cause, the extent and the impact of these induced non-uniformities are discussed for the different discontinuous surfaces considered.