Small-signal gain and numerical simulation of transvertron high power microwave sources

The transvertron oscillator or amplifier is a novel and efficient type of intense relativistic electron-beam-driven microwave radiation source. In the m=0 asymmetric version, it consists of single or multiple cylindrical cavities driven at one of the TM_0np resonances by a high-voltage low-impedance electron beam. There is no applied magnetic field, and the oscillatory transverse motion acquired by the axially injected electron beam is an essential part of the drive mechanism. The transvertron theory was systematically tested for a wide range of parameters. The simulations were designed to verify the theoretical predictions, assess the transvertron as a possible source of intense microwave radiation, and study its potential as a microwave amplifier. Numerical results agree well in all regards with the analytical theory. Simulations were carried out in two dimensions using CCUBE with the exception of radial loading cases, where the 3-D code SOS was required