Theoretical Study of a Plasma-Filled Relativistic Cerenkov Generator With Coaxial Slow-Wave Structure

The linear and nonlinear theory of a plasma-filled relativistic Cherenkov generator with coaxial slow-wave structure (SWS) is developed. Linear analysis includes the space-charge limiting current, dispersion relations, dispersion curves, and coupling impedance. In nonlinear theory, the electron beam space-charge effect, nonsynchronous interaction, and complex reflection coefficients of the electromagnetic wave at the boundaries of the SWS are taken into account. With the assumption of quasi steady state, the self-consistent equations are numerically calculated using the fourth-order Runge-Kutta method. The effects of the relative phase between inner and outer corrugations, phase and amplitude of the complex reflection coefficient at the boundaries of the SWS, and plasma density on device efficiency are discussed. Efficiencies of up to 37% without plasma and about 50% with plasma density of n_p = 3-7 times 10¹¹ cm^-3 are obtained.