A Computational Study of Streamers Interacting with Dielectrics

Abstract

Electric discharges along dielectric materials are common phenomena in electronics and high-voltage equipment. We here developed a 2D plasma fluid model to study the dynamics of both positive and negative surface streamers. The model is based on the Afivo-streamer code1, and improved to include dielectrics2. We simulate the process of streamers interacting with dielectrics, including inception besides the dielectric, attaching to and propagation over the dielectric surface. The results show that both positive and negative streamers are attracted by dielectrics. After attaching to the dielectric, both of them become thinner and faster, and the maximum electric field and electron density at the streamer head become higher than in bulk gas. However, positive streamers attach to the dielectric more rapidly, and have higher electric field and propagation velocity than negative streamers. In addition, a zone with high electric field but low electron density presents between positive streamers and dielectric surfaces. However, for a negative surface streamer, the maximum electron density shows up near the interface, while a strong electric field area presents inside the dielectric around the streamer head.