Plasma-wall transition and sheath formation

TL;DR

This paper reviews the theoretical and computational understanding of plasma-wall transitions, including sheath formation and regimes, with applications to electrostatic probe theory and ion temperature measurement effects.

Contribution

It provides a comprehensive overview of plasma sheath regimes, conditions for sheath existence, and introduces a kinetic model for electrostatic probe analysis.

Findings

Conditions for plasma sheath existence established

Analysis of collisionless and collisional regimes

Impact of probes on ion temperature measurements studied

Abstract

A review of the theoretical and computational aspects of plasma-wall transition is presented. The conditions for the existence of plasma sheaths in front of a solid surface are established. Various regimes are analyzed -collisionless and collisional. fluid and kinetic, with and without ionization. The partition of the plasma-wall transition into distinct regions (Debye sheath, quasineutral presheath. magnetic presheath, etc...) is also discussed. Applications to the theory of electrostatic probes are illustrated by means of a recently developed kinetic model. The influence of the probe on ion temperature measurements is studied in detail.