A Computational Study of Negative Surface Discharges: Characteristics of Surface Streamers and Surface Charges

TL;DR

This study uses numerical simulations to analyze negative surface discharges, revealing their distinct characteristics compared to bulk gas streamers and how surface charge influences their development.

Contribution

It provides new insights into the behavior of negative surface streamers and the effects of surface charge and dielectric properties on their dynamics.

Findings

Negative surface streamers have higher electron density and propagation velocity than bulk negative streamers.

Surface charge accumulation can delay or inhibit streamer growth.

Negative surface charge increases electric field inside the dielectric.

Abstract

We investigate the dynamics of negative surface discharges in air through numerical simulations with a 2D fluid model. A geometry consisting of a flat dielectric embedded between parallel-plate electrodes is used. Compared to negative streamers in bulk gas, negative surface streamers are observed to have a higher electron density, a higher electric field and higher propagation velocity. On the other hand, their maximum electric field and velocity are lower than for positive surface streamers. In our simulations, negative surface streamers are slower for larger relative permittivity. Negative charge accumulates on a dielectric surface when a negative streamer propagates along it, which can lead to a high electric field inside the dielectric. If we initially put negative surface charge on the dielectric, the growth of negative surface discharges is delayed or inhibited. Positive surface charge has the opposite effect.