Simulating streamer discharges in 3D with the parallel adaptive Afivo framework

Abstract

We present an open-source plasma fluid code for 2D, cylindrical and 3D\nsimulations of streamer discharges, based on the Afivo framework that features\nadaptive mesh refinement, geometric multigrid methods for Poisson's equation,\nand OpenMP parallelism. We describe the numerical implementation of a fluid\nmodel of the drift-diffusion-reaction type, combined with the local field\napproximation. Then we demonstrate its functionality with 3D simulations of\nlong positive streamers in nitrogen in undervolted gaps, using three examples.\nThe first example shows how a stochastic background density affects streamer\npropagation and branching. The second one focuses on the interaction of a\nstreamer with preionized regions, and the third one investigates the\ninteraction between two streamers. The simulations run on up to $10^8$ grid\ncells within less than a day. Without mesh refinement, they would require\n$4\\cdot 10^{12}$ grid cells.\n