Electron kinetics at the plasma interface

TL;DR

This paper investigates the microscopic electron transfer processes at plasma-wall interfaces, focusing on the formation and structure of the plasma sheath and electric double layer, advancing understanding of plasma-electrode interactions.

Contribution

It provides a microscopic analysis of charge transfer processes at plasma-wall interfaces and explores the negative part of the electric double layer inside the wall.

Findings

Identification of key charge transfer mechanisms

Initial steps towards modeling the negative layer inside the wall

Discussion of future research directions

Abstract

The most fundamental response of an ionized gas to a macroscopic object is the formation of the plasma sheath. It is an electron depleted space charge region, adjacent to the object, which screens the object's negative charge arising from the accumulation of electrons from the plasma. The plasma sheath is thus the positively charged part of an electric double layer whose negatively charged part is inside the wall. In the course of the Transregional Collaborative Research Center SFB/TRR24 we investigated, from a microscopic point of view, the elementary charge transfer processes responsible for the electric double layer at a floating plasma-wall interface and made first steps towards a description of the negative part of the layer inside the wall. Below we review our work in a colloquial manner, describe possible extensions, and identify key issues which need to be resolved to make further progress in the understanding of the electron kinetics across plasma-wall interfaces.