Patent Number: 
Section: claims

1. A plasma generation system comprisinga shock coil having an annular disc shaped body bounded by an outer ring formed about an outer periphery of the body and an annular hub formed about an inner periphery of the body and a coil of parallel wound wires attached to a face of the body, anda Laval nozzle for introducing gas to the shock coil, the nozzle comprising an annular disc-shaped nozzle body coupled about an inner periphery of the nozzle body to the hub and forming with the hub about an outer periphery of the nozzle body a radially oriented annular nozzle outlet positioned adjacent the inner periphery of the body of the shock coil, wherein the nozzle is oriented to radially discharge a gas across the surface of the coil from the inner toward the outer periphery of the body of the shock coil, wherein when a gas is discharged across the surface of the coil and the coil is energized an annular plasma is ejected from the surface of the coil. 2. The plasma generation system of claim 1 wherein the coil of parallel wound wires is a single-turn coil. 3. The plasma generation system of claim 2 wherein the coil of parallel wound wires is a multi-strand coil. 4. The plasma generation system of claim 1 wherein the wires of the coil of parallel wound wires begin adjacent an outer radius of the body at angularly spaced points and encircle the face of the body one turn ending at an inner radius of the body. 5. The plasma generation system of claim 4 wherein the wires of the coil of parallel wound wires begin at the perimeter of the body. 6. The plasma generation system of claim 1 wherein a face of the nozzle body facing the hub forms an annular shaped gas plenum and a constricting-expanding nozzle with a face of the hub. 7. The plasma generation system of claim 6 further comprising a plurality of gas channels formed in the hub and in communication with the gas plenum. 8. The plasma generation system of claim 7 further comprising a valve seat ring having a plurality of valve seats aligned with the plurality of gas channels. 9. The plasma generation system of claim 1 further comprising a shroud coupled to the outer ring. 10. The plasma generation system of claim 1 wherein the shock coil is configured to fire the wires in a synchronized manner. 11. The plasma generation system of claim 1 wherein the wires are combined into a plurality of groups of wires that are azimuthally symmetric about the surface of the shock coil.