Non-conventional diagnostics of energy and momentum transfer at particle-surface interactions

Abstract

Summary form only given. The forces that low-temperature plasmas exert on limiting walls and electrodes have not received much attention so far. The reason might be the smallness of such forces and the expected difficulties in their measurement. Therefore, only in cases of special plasmas which were designed for the generation of directed momentum (electric space propulsion), measurements of the force exerted by the plasma on a surface have been reported, e.g. Recently, our group demonstrated that the forces related to plasma-wall interactions are experimentally accessible with some effort. This presentation overviews our experimental approaches in the design of force measuring probes* and reports on recent measurements with probes that have been integrated into a plane wall. The observations are discussed in the light of plasma sheath models as well as prospects for an application as novel plasma diagnostic. The energy, on the other hand, that a plasma transfers to solid surfaces, has already been subject of several investigations for a long time and calorimetric probes have increasingly been applied for plasma diagnostics. Calorimetric and force probes, which are alike in some aspects, are discussed from the viewpoint of momenta of velocity distribution functions.