Theoretical analysis of a relativistic travelling wave tube filled with plasma

A cold and uniform plasma-filled travelling wave tube withsinusoidally corrugated slow wave structure is driven by a finitethick annular intense relativistic electron beam with the entiresystem immersed in a strong longitudinal magnetic field. By means ofthe linear field theory, the dispersion relation for the relativistictravelling wave tube (RTWT) is derived. By numerical computation, thedispersion characteristics of the RTWT are analysed in differentcases of various geometric parameters of the slow wave structure andplasma densities. Also the gain versus frequency for three differentplasma densities and the peak gain of the tube versus plasma densityare analysed. Some useful results are obtained on the basis of thediscussion.