Experiments were made on an electric arc applying a porous graphite anode cooled by a transpiring gas (Argon). Thus, the energy transferred from the arc to the anode was partly fed back into the arc. It was shown that by proper anode design the net energy loss of the arc to the anode could be reduced to approximately 15% of the total arc energy A detailed energy balance of the anode was established. The anode ablation could be reduced to a negligible amount. The dependence of the arc voltage upon the mass flow velocity of the transpirating gas was investigated for various arc lengths and currents between 100 Amp and 200 Amp. Qualitative observations were made and high-speed motion pictures were taken to study flow phenomena in the arc at various mass flow velocities.

The high heat fluxes existing at the electrode surfaces of electric arcs necessitate extensive cooling to prevent electrode ablation. The cooling requirements are particularly severe at the anode. In free burning electric arcs, for instance, approximately 90% of the total arc power is transferred to the anode giving rise to local heat fluxes in excess of **f as measured by the authors -- the exact value depending on the arc atmosphere. In plasma generators as currently commercially available for industrial use or as high temperature research tools often more than 50% of the total energy input is being transferred to the cooling medium of the anode.