Characterization of a rotating gliding arc in argon at atmospheric pressure

The dynamics of a low-power (< 40 W) rotating gliding arc in atmospheric pressure argon sustained by a homemade dual DC power supply between a conical cathode and a grounded sleeve anode and forced into motion by the combined action of a vortex gas flow (< 26.3 SLPM) and axial magnetic field (similar to 0.043-0.122 T) was studied. High-speed imaging and electrical diagnostics were used to gain an understanding of the projected arc length, position of the attachment point on the central cathode, and frequency of arc rotation. The electrical signals revealed a glow-type mode of operation, which characteristically low current and high voltage. The square root dependency of the rotating arc frequency on the applied current predicted by a simplified model considering the gas vortex drag and Lorentz forces was confirmed with measurements. Rotation frequencies in the similar to 100-300 Hz range with average projected arc lengths of 4-8 mm creating a large stabilized reactive volume were obtained. We further demonstrated that the Lorentz force acting on the rotating gliding arc is equivalent to the hydrodynamic drag caused by an argon flow rate of similar to 8 SLPM for this device configuration.