A Novel Scheme to Reduce the Electron Loss and Power Amplification in an Axial Virtual Cathode Oscillator

In this study, reuse of the escaping electrons for the formation of the second virtual cathode (VC-2) was presented. To achieve this, a reflector made up of dielectric material was designed and installed inside the drift tube downstream region. the drifting electrons formed a VC-2 when they are accumulated at the surface of the dielectric reflector as a wall charge. Interestingly, the electromagnetic wave interacted with the charge of VC-2 and its amplitude is increased approximately four times than the conventional one. With the presented technique, the achievable vircator efficiency is more than 20 %.