Abstract: A material processing apparatus having an integrated toroidal plasma source is described. The material processing apparatus includes a plasma chamber that comprises a portion of an outer surface of a process chamber. A transformer having a magnetic core surrounds a portion of the plasma chamber. The transformer has a primary winding. A solid state AC switching power supply comprising one or more switching semiconductor devices is coupled to a voltage supply and has an output that is coupled to the primary winding. The solid state AC switching power supply drives an AC current in the primary winding that induces an AC potential inside the chamber that directly forms a toroidal plasma that completes a secondary circuit of the transformer and dissociates the gas.

Abstract: The invention relates to a method for welding a double layer sheet metal (1, 2) having an intermediate layer (5), in particular, a sheet metal with knobs, with a bonding sheet metal (8) by spot or roll seam welding. Before welding of the bonding sheet metal (8) with the two cover sheet metals (1, 2), spaced apart by the intermediate layer (5) of the double layer sheet metal, is carried out, the area (11) about the welding location (12) is burned free of the intermediate layer (5) by the current which is introduced over a large surface area into the cover sheet metals (1, 2) via the welding electrodes (9, 10) placed thereat and guided via a shunt adjacent to the welding location (12). Only thereafter, the sheet metals are brought into conducting contact with one another by a directed local pressure application, and the welding process is carried out.