Electrode assembly for plasma generation

Abstract

A hollow electrode assembly through which gas from a gas supply can pass and be effused across the casing of the electrode for supplying a gas for a plasma discharge. The gas passing the electrode goes from a higher gas pressure environment inside the electrode to a lower gas pressure environment on the outside of the electrode. The casing of the electrode through which the gas effuses can be a metal or metal allow which provides for a controlled flow of the gas through the wall. The flow rate of the gas can be controlled by one or more of the porosity of the metal or metal alloy used, the type of gas used, the pressure differential between the inside and outside of the electrode, and the temperature of the system. The electrode assembly can be used in and high temperature plasma generators.

What is claimed is: 
     
         1 . An electrode apparatus for plasma generation comprising:
 a hollow electrode assembly connectable to a gas source, comprising,   at least one conduit in the hollow electrode assembly for supplying gas under pressure to the inside of the hollow electrode assembly,   a gas permeable membrane on the electrode for permitting gas from inside the assembly to effuse across the membrane for supply gas to a plasma discharge from the electrode.   
     
     
         2 . The electrode apparatus of  claim 1 , wherein the electrode further comprises a plasma discharge head from which the plasma is discharged from the electrode. 
     
     
         3 . The electrode apparatus of  claim 2 , wherein the gas permeable membrane comprises a head composed of a pure element or alloy selected from the group consisting of nickel, iron, carbon, molybdenum, chromium, vanadium, silicon, copper, palladium, platinum, lithium, aluminum, carbon and combinations thereof. 
     
     
         4 . A method for generating a plasma comprising:
 providing a hollow electrode assembly through which a gas from a gas supply can pass and be effused across the casing of the electrode for supplying a gas for a plasma discharge,   introducing the gas under pressure into the electrode assembly such that the gas passes and is effused across the casing, and   applying a current and a voltage to the electrode assembly for generating a plasma discharge.