A boundary value "reservoir problem" and boundary conditions for multi-moment multifluid simulations of sheaths

TL;DR

This paper investigates boundary conditions for multifluid plasma sheath simulations, demonstrating that vacuum boundary conditions can effectively model absorbing walls with accuracy comparable to more complex sheath models.

Contribution

It provides a justification for using vacuum boundary conditions in multifluid plasma sheath simulations, simplifying boundary treatment while maintaining accuracy.

Findings

Vacuum boundary conditions yield comparable accuracy to classical sheath models.

Multifluid simulations can effectively model plasma-wall interactions with simplified boundary conditions.

The approach enhances computational efficiency in plasma sheath modeling.

Abstract

Multifluid simulations of plasma sheaths are increasingly used to model a wide variety of problems in plasma physics ranging from global magnetospheric flows around celestial bodies to plasma-wall interactions in thrusters and fusion devices. For multifluid problems, accurate boundary conditions to model an absorbing wall that resolves a classical sheath remains an open research area. This work justifies the use of vacuum boundary conditions for absorbing walls to show comparable accuracy between a multifluid sheath and lower moments of a continuum-kinetic sheath.