Plasma-surface interactions play an important role in a variety of industrial applications of plasma physics, including plasma deposition and etching, surface modification by plasma ion implantation, plasma switching devices, and the use of thermal plasmas for materials processing and metallurgy, as well as in plasma diagnostics using probes. A fundamental understanding of the interaction of the plasma with the surface is required in order to optimize and develop these techniques to their fullest potential. This grant will involve a theoretical and numerical investigation of plasma-surface interactions, sheaths, and pre-sheaths (both steady- state and time-dependent) using a kinetic description. In particular, the role of Coulomb collisions and ion-neutral interactions in affecting the flow of plasma to surfaces, the energy distribution of the ions arriving at the surface, and the establishment of long-range electric fields in the plasma as well as the electric field in the sheath itself, will be investigated. It is planned to utilize a kinetic description in order to connect to existing collisionless and fluid models for plasma-flow to the surface. The work on time dependent effects will focus on RF sheaths and pre-sheaths when the applied frequency is above and below the ion plasma frequency. This work will be jointly supported by the Interfacial, Thermodynamics, and Transport Program within the CBTE Division.
