In this paper, the dispersion relation of the relativistic travelling-wave tube (RTWT) and relativistic backward-wave oscillator (RBWO) filled with plasma is obtained in the presence of an annular electron beam and solved by an exact numerical solution. The interaction of the beam with the waveguide modes is clearly identified and beam line splitting into the slow and fast waves is observed. In addition, the growth rates of each structure are investigated. The results show that the effect of plasma on the temporal growth rate of the TM 01 mode in the RBWO is negligible and the higher modes are not affected. Conversely, the spatial growth rate in the RTWT increases significantly with the plasma density.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.