Plasma–Wall Interaction Model for Erosion of Materials Under Ion Bombardment

Abstract

Understanding the evolution and behavior of materials exposed to plasma is critical for the design of future electric propulsion devices. As ions are ejected from the device generating thrust, they also impact the ceramic walls. This induces wall erosion, ultimately exposing the magnetic circuit, leading to malfunction and failure of the device. There are several models that try to predict this effect by accounting for material sputtering. However, they cannot predict the millimeter-scale surface features that develop after prolonged exposure. In this work, we address this issue by introducing a plasma–material interaction model able to capture the evolution of surface features at the macroscopic scale on materials exposed to plasma over a long period of time. Results show that the model is able to reproduce not only the mean erosion rate but also the macroscopic anomalous ridges that appear after long exposure. Furthermore, it highlights the need to account for complex thermomechanical material behavior to be able to explain such features.