Proof of Principle Experiments on Direct Generation of the $\hbox {TE}_{11}$ Mode in a Coaxial Vircator

Experiments on a coaxial vircator with a sectioned emitter are reported. The emitting area is sectioned to form two opposing emitters in order to favor growth of the TE₁₁ mode and inhibit growth of the TM₀₁ mode that is usually excited in a coaxial vircator. Experiments are performed using a compact 320-J 400-kV Marx generator and a compact coaxial vircator built in a standard 8^" vacuum tube. The radiated magnetic-field strength is measured by means of four free-field (B-dot) probes, and experiments show that sectioning the emitter does, in fact, lead to generation of the TE₁₁ mode.