Instabilities driven by an intense beam in a plasma-filled dielectric-lined waveguide immersed in a finite axial magnetic field

A linear analysis is described on instabilities driven by an intense relati vistic electron beam in an infinitely long, plasma-filled, and dielectric-l ined circular waveguide immersed in a finite strength axial magnetic field. A dispersion equation is derived from the cold fluid theory and solved num erically. Beam-plasma instabilities due to interaction between beam modes a nd the Trivelpiece-Gould modes appear as well as the Cherenkov and the cycl otron Cherenkov instabilities. Parametric researches are carried out varyin g magnetic field strength, plasma density, and dielectric constant. Effects of a finite magnetic field and plasma filling are discussed in connection with the possibilities of using this system as a microwave radiation source .