Plasma generating apparatus

Apparatus for generating a plasma via the transient hollow cathode discharge effect, the apparatus comprising:

• a chamber comprising an inlet configured to allow a gas to enter the chamber and an outlet configured to allow the gas to exit the chamber;
• a cathode electrode disposed in the chamber, the cathode electrode comprising a plurality of hollow cathodes each comprising a through-thickness hole through configured to allow the gas pass from one side of the cathode electrode to another side of the cathode electrode, wherein the apparatus is configured so as to define a gas flow pathway passing from the inlet to the outlet through the plurality of hollow cathode through-thickness holes;
• an anode electrode spaced apart from the cathode;
• a power supply electrically connected to the anode electrode and the cathode electrode for supplying electrical power to generate a plasma at the plurality of hollow cathodes;
• and
• a power supply controller configured to reduce a power level of the electrical power below a first power level required to maintain the plasma at the plurality of hollow cathodes, after electrical breakdown has occurred and wherein the plurality of hollow cathodes are arranged into a plurality of groups of hollow cathodes and the cathode electrode comprises a plurality of electrically conducting pathways, each one of said electrically conducting pathways connecting the hollow cathodes within one group to each other for supplying the electrical power to said group of hollow cathodes, and wherein the hollow cathodes of neighboring groups are spaced apart from one another by an electrically insulating region.