Particle-in-cell simulation of bipolar dc corona

Most of the existing methods for calculating dc ionized fields of monopolar and bipolar corona have ignored the ionization regions and excluded the transient phenomena of corona discharges. In this paper, bipolar dc corona was studied with a two-dimensional particle-in-cell simulation, which allowed us to model time-dependent, nonlinear, microscopic phenomena involved in the corona discharge. The technique followed simulation particles that represented electrons, positive ions, and negative ions, and self-consistently calculated the associated electric field that determined the simulation particle motion. Finite element and charge simulation methods were used to solve Poisson´s equation while a finite difference scheme was applied to move simulation particles. Multi-scale techniques (nonuniform triangle mesh and variable time step) were employed to reduce numerical noise and increase simulation efficiency. The particle-in-cell simulation was applied to a cylindrical bipolar corona cage problem. Simulation results included one primitive streamer, multi-electrode induced currents, conductor temperature effects, memory effects, the approach to a stationary state, and transient corona saturation