Frequency Dependence of the Anode-Cathode Gap Spacing in a Coaxial Vircator System

The objective of this paper was to investigate how the frequency of an electromagnetic pulse generated by an inward-emitting coaxial vircator is dependent upon the anode to cathode gap distance (AK-gap) in the vircator. Experimental tests of three different AK-gaps 29.5, 32, and 34.5 mm, were conducted with the high power microwave (HPM) system Bofors HPM Blackout. The system is working within the L- to S-band and the vircator is powered by a 1.8-kJ Marx generator at a maximum voltage of 600 kV. In addition, the experimental models of the coaxial vircators were also simulated in ATK MAGIC2D particle-in-cell code and the experimental frequency was compared with the theoretical frequency. The experimental frequency increased with decreasing AK-gap.