2-D Particle Simulation on the Influence of Transverse Magnetic Field on the Plasma Decay in Postarc Stage of Vacuum Circuit Breakers

In this article, the plasma decay in the postarc stage of vacuum circuit breakers and the influence of the transverse magnetic field (TMF) on this process are investigated with a 2-D particle-in-cell model. In this model, distributions of electric field and plasma are solved by Poisson's equation and Newton's law, respectively, in 2-D Cartesian coordinate system. The distributions of charged particles and the velocity of the sheath development in the simulation without magnetic field in this article agree well with those in the simulation solved in cylindrical coordinate system in the published work. The TMF in the postarc phase leads to asymmetric distributions of charged particles, which slows down the plasma decay process in the postarc phase. In addition, the TMF results density fluctuations in the plasma and makes the plasma discontinuous and cluster, which can disturb the ion sheath near the postarc anode and result the local electric fields in the plasma. Electrons can be accelerated and gain high velocities in these local fields. These effects of TMF will slow down the dielectric recovery in the postarc stage of vacuum circuit breakers and may increase the risk of rebreakdown in the postarc stage when the vacuum circuit breaker interrupts large fault currents.