Linear theory of plasma filled Coaxial Cerenkov Maser

Summary form only given. Linear dispersion relation of transverse magnetic (TM) modes in a plasma filled Coaxial Cerenkov Maser (CCM) driven by an intense relativistic annular electron beam has been derived. A special low frequency (LF) slow mode has been found to exist in the device along with the usual high frequency TM modes even in the absence of the background plasma. With the increase of relative dielectric constant of the filling material in the CCM, the dispersion curve of this LF slow mode is found to shift downward. The effects of the dielectric material and its radial thickness, radial position of the electron beam, and the background plasma on the dispersion characteristics of the LF and TM/sub 01/ modes in CCM have been investigated. The operating frequency and the temporal growth rate of the wave in the device for a fixed beam velocity and position are found to increase slowly with the decrease in relative dielectric constant. With the decrease of the transverse dimension of the dielectric material, the operating frequency increases for both LF and TM/sub 01/ modes, while their growth rates are found to decrease. The growth rates of both LF and TM/sub 01/ modes increase without any appreciable change in the operating frequency with the increase in the radial position of the electron beam. The presence of the background plasma in the slow wave structure enhances the temporal growth rates of both LF and TM/sub 01/ modes without any change in operating frequencies.