Negative energy cyclotron resonance maser

A novel high power cyclotron resonance device is introduced which requires zero initial transverse velocity, tolerates a large beam velocity spread, and can yield a large cyclotron frequency upshift ratio. The negative energy cyclotron wave will couple to a positive energy, slow waveguide mode with a growth rate which can be even larger than the space charge mode for intense, high-voltage electron beams. 2-D fluid theory, 1-D Vlasov theory, and 1 1/2-dimensional simulations are presented along with the design parameters for a proposed proof-of-principle experiment.<>