Time-dependent Magnetohydrodynamic Simulation of SF6 Rotary-arc Plasma with Consideration of Electromotive Force

We have carried out time-dependent three-dimensional magnetohydrodynamic numerical simulations of rotary arc plasma in a simple chamber filled with SF6 or CO2 gas under an externally applied magnetic field. In the numerical simulations for both the gas conditions, the arc current and the strength of applied magnetic field are set to DC 2 kA and 1.2 T, respectively. In this paper we show that the rotation of arc plasma induced by applying the magnetic field increases the arc voltage and the gas pressure in the chamber, and also these phenomena with applying the magnetic field are much clearly observed in CO2 gas than SF6 gas. Furthermore, we show from the numerical simulations of rotary arc plasma in SF6 gas that the rotational speed of arc plasma becomes slow by accounting for the electromotive force induced by the MHD interaction, but the induced electromotive force has only a little influence on the arc voltage and the gas pressure in the chamber.