Physisorption kinetics of electrons at plasma boundaries

TL;DR

This paper introduces a quantum-kinetic model to describe how electrons accumulate at plasma boundaries, focusing on electron sticking and desorption, with implications for understanding surface charge formation.

Contribution

It presents a novel physisorption-inspired quantum-kinetic approach to model electron surface interactions at plasma boundaries, providing microscopic insights into electron sticking and desorption.

Findings

Calculated electron sticking coefficient and desorption time for metallic boundaries.

Identified key issues in electronic microphysics at plasma boundaries.

Proposed a microscopic model to inspire further research.

Abstract

Plasma-boundaries floating in an ionized gas are usually negatively charged. They accumulate electrons more efficiently than ions which leads to the formation of a quasi-stationary electron film at the boundaries. We propose, in a colloquial manner, a physisorption-inspired quantum-kinetic description of the build-up of surface charges at inert plasma boundaries and calculate the electron sticking coefficient and the electron desorption time, which play an important role in determining the quasi-stationary surface charge, and about which little is empirically and theoretically known, from a microscopic model for the electron-wall interaction. In an exploratory calculation we specifically consider a metallic boundary. But thereby we identify quite generally what we believe are the key issues of the electronic microphysics at inert plasma boundaries in the hope to inspire other groups to join us on our journey.