Abstract: A waveguide structure has at least one shaped slot machined in the wall of the waveguide. The slot is configured such that a high voltage is generated across the slot when the waveguide is suitably excited with high-power microwaves. The strong electric fields generated in the region of the slot can be used to produce a non-equilibrium plasma discharge in a working gas introduced in the vicinity of the slot. Various substrates can be translated past the slot and exposed to the plasma species generated by the microwave discharge. The slotted waveguide structure is designed to operate as a traveling wave structure with microwave energy uniformly dissipated along the length of the slot. Several methods are disclosed for providing uniform power dissipation. These methods include changing the dimensions of the waveguide, altering the position and shape of the wall slot, coupling power into the waveguide by means of auxiliary sources, and using an auxiliary ground plane.

Abstract: A single channel double-duct liquid metal electrical generator using a magnetohydrodynamic (MHD) device. The single channel device provides useful output AC electric energy. The generator includes a two-cylinder linear-piston engine which drives liquid metal in a single channel looped around one side of the MHD device to form a double-duct contra-flowing liquid metal MHD generator. A flow conduit network and drive mechanism are provided for moving liquid metal with an oscillating flow through a static magnetic field to produce useful AC electric energy at practical voltages and currents. Variable stroke is obtained by controlling the quantity of liquid metal in the channel. High efficiency is obtained over a wide range of frequency and power output.