Plasma sheath studies using a physical treatment of electron emission from a dielectric wall

TL;DR

This paper models plasma sheath formation near dielectric walls by incorporating quantum-mechanically derived low-energy electron reflection, revealing how material properties influence sheath structure and particle distributions in plasma applications.

Contribution

It introduces a boundary condition based on quantum mechanical principles for electron reflection, enabling more accurate sheath simulations for dielectric materials.

Findings

Material properties significantly affect sheath profiles.

High electron reflection leads to space-charge limited sheaths.

Simulation results highlight the importance of low-energy electron interactions.

Abstract

When a plasma sheath forms next to a dielectric wall, material properties determine electron absorption and reflection from the surface, impacting the sheath formation and structure. The low energy regime of this interaction is often not considered rigorously in emissive sheath simulations, but may be modeled from quantum mechanical first principles, and has important applications to plasma thrusters and fusion devices. In this work, low energy electron reflection from the wall is implemented as a boundary condition in a continuum kinetic framework and the sheath is simulated for dielectric material parameters in high and low emission cases. The results presented here demonstrate that the material parameters can have significant effect on the resulting sheath profile and particle distribution functions. Surfaces with high reflection rates see the formation of a space-charge limited sheath.