What Keeps an Arc Standing in a Cross Flow?

An arc exposed to a flow perpendicular to its axis takes on a curved shape. If, however, the electrodes of the arc are moved in a quiet atmosphere, the arc follows the electrodes showing the curved shape as well. Obviously it is just the relative motion between arc and atmosphere that produces a curved arc. Since the flow continues penetrating the arc even in the final curved configuration, the arc cannot be intensified. This is achieved by gradients of ohmic heating and heat as finite temperature distribution. In order to withstand the mass flow, the heating in the front and the cooling in the rear of the arc have to be intensified. This is achieved by gradients of ohmic heating and heat conduction across the arc caused by the curvature. For a complete description of this phenomenon, the compensation flow due to expansion and contraction of the gas penetrating the arc has to be taken into account. This compensation flow increases the relative velocity considerably. The mass flow through the arc and the curvature due to it can also be produced by a cross magnetic field or by buoyancy acting on a horizontal arc.