Particle modeling of vacuum arc discharges

Abstract

Metal vapor vacuum arcs (VAs) are widely used in various fields of industry, such as circuit breakers, ion sources, electrical thrusters, and deposition systems. VAs usually originate from metal vapors eroding from the surface of a cathode, where they burn as tiny bright points, hence their name “cathode spots” (CS). Due to their high plasma density, short life span, and micrometer scale, the in situ and non-intrusive diagnostics of CS are a challenge. Numerical simulation is one method used to study CS with the aid of high-performance computing. The well-established particle-in-cell method provides solutions for the spatial-temporal electromagnetic field and the microscopic distribution functions of plasma species in phase space from which the macroscopic parameters of the plasma can be calculated. This Perspective reviews the progress in particle modeling of VAs with an emphasis on the non-stationary and non-local physical processes that are not reproduced by fluid models. Furthermore, a personal outlook on future challenges is provided: the physical modeling of plasma–electrode interactions, the collection and evaluation of collision cross sections, the trade-off between heavy computation cost and predictive ability, and the verification and validation of the simulation code.