Numerical study of the oscillation characteristics of a surface wave oscillator

Abstract

The oscillation characteristics of a surface wave oscillator is analyzed numerically. The oscillation frequency due to Cherenkov instability can be controlled by the electron beam energy though the alteration of the accompanying temporal growth rate. The growth rate increases exponentially with the proximity of the beam to a corrugated metal plate. The oscillation frequency is not changed by this proximity. The peak of the growth rate of the Cherenkov instability is one or more orders higher than that of a Smith-Purcell type instability. Moreover, in frequency and wavenumbers, the difference of two instabilities is enlarged by the increase in the growth rate. Therefore, the influence of the Smith-Purcell type instability on the Cherenkov instability is decreased. 