Linear investigations of the Cyclotron Autoresonance Maser amplifiers with coaxial structure

In this paper, we present the linear investigation of the cyclotron autoresonance maser (CARM) amplifiers with coaxial structure. The linear kinetic theory and the nonlinear simulation are used together for the power growth prediction. It is shown that the power behaviors predicated by the kinetic theory in the linear regime of the interaction of operating mode TE_28,16 with 90-kV, 50A, alpha = 0.85 electron beam agreed well with its nonlinear simulation. The difference of the power obtained by the linear theory and nonlinear simulation at the saturate interaction length 30 cm is less than 17%. The power growth profile agrees very well with these two approaches when the device operates in lower order modes, i.e., TE₂₁ etc.