ИСТИНА

1. A DC arc plasmatron comprising:a rod cathode,a nozzle anode having a body member and a through axial a power supply unit connected to both of the rod cathode and the nozzle anode, and a gas system for feeding plasma-forming gas into a space between the rod cathode and the nozzle anode and supplying suitably selected functional gas into the anode orifice through an internal opening communicating with said anode orifice and positioned between inlet and out let par‘ts of said anode orifice, wherein said internal opening is configured as an annular gap between said inlet and outlet parts of said anode orifice, while said annular gap has a predefined size relative to a diameter of the inlet part of said anode orifice and the outlet part of said anode orifice has a predefined diameter relative to the diameter of the inlet part of said anode orifice, wherein said anode is configured such that the ratio of the size G of said annular gap to the diameterA of the inlet part of said anode orifice is between 0.3 to 3. 2. A DC are plasmatron as claimed in claim 1, wherein said anode is configured such that the ratio of the diameters D to A of the outlet and inlet parts of said anode orifice respectively is between 0.3 to 3. 3. A DC arc plasmatron as claimed in claim 1, wherein said annular gap is formed as a vortex injector. 4. A DC arc plasmatron as claimed in claim 3, wherein said vortex injector has tangential inlet holes. 5. A DC arc plasmatron as claimed in claim 3, wherein said vortex injector has a supplying auger at its inlet. 6. A DC arc plasmatron as claimed in claim 1, wherein internal surfaces of said gap are shaped flat to direct functional gas at an angle relative to a principal axis of the orifice, thus providing Wake or cross How of functional gas with respect to the axial movement of the plasma-forming gas through the orifice. 7. A method of using said DC arc plasmatron as claimed in claim 1, comprising the steps of: selecting a suitable functional gas; switching on the gas system of the plasmatron; and exciting an arc discharge betWeen the anode and the cathode by applying a voltage betWeen the anode and the cathode using the power supply unit, wherein the above steps are carried out at atmospheric pressure in an arc discharge area, then process parameters are adjusted to a given level and the arc discharge area is evacuated through the anode orifice while keeping the above process parameters until suitable vacuum pressure in the arc discharge area is reached. 8. A DC arc plasmatron as claimed in claim 1, wherein internal surfaces of said gap are shaped conical to direct functional gas at an angle relative to a principal axis of the orifice, thus providing wake or cross how of functional gas with respect to the axial movement of the plasma-forming gas through the orifice.