The design of a 10-20-MW 40-ns cyclotron auto-resonance maser (CARM) is presented. The basic components of CARM are a pulseline accelerator, magnetic-field coils, a novel 600-kV 200-A field-emission electron gun designed for p┴/pz = 0.6 and ∆pz/pz < 3 percent, and a “whispering-gallery” mode rippled-wall cavity, designed for a high Q for the desired CARM mode and low Q for competing gyrotron modes. The NRL CARM operates with a wave group velocity that is less than optimum for autoresonance, but where the cyclotron maser instability is strong. By keeping the interaction region short (less than 10 cyclotron orbits), the effect of velocity spread is reduced, and the efficiency can be quite high; computer simulations indicate that the device will operate at efficiencies greater than 20 percent.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Electrical and Electronic Engineering