A coaxial-waveguide cyclotron autoresonance maser (CARM) amplifier

A new concept of gyro-devices in the form of a coaxial-waveguide cyclotron autoresonance maser (CARM) is proposed, which may be well suited for operation at both high power and ultrahigh gain in the millimeter wave and far infrared regions. Example is presented for a coaxial configuration - with outer and inner radii of 1.83 cm and 0.50 cm - designed to operate in the TE_28,16 mode at 335 GHz, yielding a gain of 64 dB on using a 90 keV and 50 A electron beam confined by a 9.35 T magnetic field. Nonlinear simulation demonstrates the possibility of power enhancement via a tapered magnetic field and the suppression of the degenerate mode as well as the absolute instability.