Magnetic Field Stabilization Of Low Current Dc Arc Discharge In Cross Flow In Argon Gas At Atmospheric Pressure-A Numerical Modelling Study

In this work we study the effect of an external magnetic field and gas flow on the properties of a low current DC (gliding) arc discharge in argon at atmospheric pressure. We consider a cross flow configuration, in which argon gas flows perpendicularly to the arc current, while the external magnetic field is perpendicular to both the arc current and the gas flow. The study is based on a 2D numerical fluid plasma model of the discharge, coupled with a gas flow model based on the Navier-Stokes equations and a gas thermal balance equation. In the examined configuration, a stabilized arc is achieved by having the E x B drift acting in opposite direction to the gas flow, i.e. the Lorentz force pushing the arc against the gas flow. The numerical model was implemented into a finite element simulation, using the Comsol Multiphysics (version 5.3) package. The results proved that a magnetically stabilized arc can be sustained and that the examined configuration can be used for effective gas treatment. The analysis of the simulation data helped to answer multiple questions, related to arc stability, the energy density distribution in the arc, and the macroscopic properties of the system as a whole. The results show a significant influence of the walls on the arc stabilization, while in the case of walls positioned very far from the arc, i.e. unbounded channel, the arc becomes a source of a fluid instability, causing vortex shedding. In general, this study provides insight on the interaction between the gas flow and the arc in a strong magnetic field. The model presented here has the potential to further the understanding of magnetically stabilized discharges and to become a basis for developing similar studies of more complex gases.