Nonlinear Study Of Cylindrical Waveguide TM-Mode Cyclotron Autoresonance Maser (CARM) Amplifier

High power sources in a range of millimeter and submillimetser waves have a great prospect of applications to radar,plasma heating,high-energy accelerator,communication,and therefore attract considerable attention in International Technology and Engineering.The devices based on the mechanism of electron cyclotron maser(ECM)—cyclotron autoresonance maser(CARM)—have the potential of high power and high efficiency for maintaining the resonance for a long distance.Recently,as the advantage, the considerable achievements have been obtained on the studies of CARM oscillator and amplifier.Previously,a great deal of attention had been paid to the transverse-electric-mode(TE-mode) gyro-devices such as gyrotron,gyropeniotron, and CARM,but very.little to the transverse-magnetic-mode (TM-mode) operation,because there is general consensus that the TM-mode is not suitable for these devices.In fact,compared to the TE-mode,the TM-mode has an axial electric field component,which may substantially affect the motion of the electrons in the axial direction when it interacts with a relativistic electron beam in a gyro-device.In the CARM mechanism,with the TM-mode,the axial component and the transverse component of electric field can exchange simultaneously energy with the electrons by beam-wave interaction,then the wave is amplified.Therefore, in principle,the use of the TM-mode is not only feasible but also maybe favorable to a CARM operation.In this paper,the main points of work and innovation are:Firstly,starting from general active wave equation,making use of the conjugate complex number of(?) and introducing a new complex number (?),a self-consistent nonlinear theoretical model for a cylindrical-waveguide CARM amplifier operating on the TM-mode is presented.The mutual interaction between beam and wave in cylindrical-waveguide is described quantitatively.Secondly,basing on the form of the theoretical,model of cylindrical-waveguide CARM amplifier with the TM-mode,the corresponding code is made of FORTRAN language and used to simulate these devices.Finally,for the TM₁,₁-mode,35GHz cylindrical-waveguide,the study of the specific nonlinear-numerical-simulation is developed.The influence of the electron beam accelerated voltage,the longitudinal guide magnet,the electron beam current,the velocity dispersion affecting on the saturated power and the interaction efficiency is analyzed.With the optimized parameters,the saturated power can be amplified to 82MW,and the interaction efficiency is 15.54%.The result shows that the use of the TM₁,₁-mode is better than the TE₁,₁-mode previously used.