Nonlinear simulation of multiple modes interaction with relativistic electron beam in THz cyclotron autoresonance maser

A nonlinear description via the self-consistent coupling equations of waves with relativistic electron beam, is provided for the nonlinear interaction of multiple modes with the relativistic electron beam in cyclotron autoresonance maser(CARM), to analyze the mode competition in CARM. Specific analysis of a sub-terahertz (0.35 THz) CARM with higher-order mode TM51 and a large-orbit electron beam shows that, contrasted with, both larger output power and higher gain can be achieved for a CARM with TM operating mode. By optimizing parameters, the operating mode can play an absolutely dominant role while the competing modes are efficiently suppressed. However, a multi-mode nonlinear simulation must be performed for a higher-order terahertz CARM, because the output power is quite sensitive to the operating parameters.