Abstract: An acoustic cannon has a plurality of acoustic sources with output ends symmetrically arranged in a planar array about a central point. Pressure pulses are generated in each acoustic source at substantially the same time. The pressure pulses exit the output ends as sonic pulses. Interaction of the sonic pulses generates a Mach disk, a non-linear shock wave that travels along an axis perpendicular to the planar array with limited radial diffusion. The Mach disk retains the intensity of the sonic pulses for a time and a distance significantly longer than that achievable from a single sonic source. The acoustic cannon is useful as a non-lethal weapon to disperse crowds or disable a hostile target.

Abstract: A method of generating high-power microwaves from a compact source is disclosed by which a transmission line cavity resonator is charged to a high voltage and an electrical switch in the resonator is closed very quickly to produce subnanosecond current risetime and a resultant high-power microwave pulse. Structure to accomplish the method is also disclosed.

Abstract: An arcjet thruster comprises a cathode body and anode body tandemly arranged and separated by an insulative propellant injection ring. The cathode body has a cathode cavity therein having a convergent and a divergent portion forming a throat therebetween. The anode body has a divergent cavity therein for producing thrust. The divergent cavity has an upstream portion and a downstream portion. The divergent portion of the cathode and the upstream portion of the anode cavity form a constrictor. A power supply connected between the anode and the cathode bodies is used to produce an arc between the anode and cathode that passes through the constrictor. Propellant is injected in a vortex flow radially into the constrictor so that it divides. A portion of the flow is directed upstream through the throat into the convergent portion of the cathode cavity thus also pushing the cathode arc attachment point into the convergent portion to cause diffuse attachment thereof.