A study of plasma-lined Cherenkov maser

We have studied the amplification of microwaves traveling along a waveguide containing a cold plasma and an electron beam confined by a strong magnetic field. The low phase velocity of the Trivelpiece-Gould modes allow for interaction with the electron beam. The pertinent parameters which influence wave amplification and dispersion are the relative transverse dimensions, plasma density, beam energy and current density, transverse mode numbers and mode frequency. Both circular and rectangular cross-sections were considered. Exact numerical solutions showed that the amplification exceeds that obtainable in the dielectric-lined guide while allowing for tunability and a better mode selection. The results of a perturbation analysis agree well with those of the exact analysis. (author)