Various characteristics of a waveguide-mode free-electron laser using a long-pulse relativistic electron beam

Selective amplification of the lower-frequency branch via stimulated super-radiance in a waveguided free electron laser oscillator driven by short electron bunches

“…Investigations into coupling/ competition between these branches have previously been reported. [3][4][5][6][7][8][9][10][11][12][13][14] Of relevance here is that it was demonstrated that for a waveguided FEL employing narrow electron bunches, the conventional FEL gain for the f − branch is small when it is located far from the cut-off frequency and when the difference between f + and f − is larger than a gain bandwidth.…”

Strong wiggler field assisted amplification in a second-harmonic waveguide free electron laser

“…Given that second-harmonic waveguide FELs are normally designed to couple with the 2 term of the electron velocity and that , the contribution of harmonic terms to the beam-wave interaction is likely to be much smaller than that of the nominal 2 term. Thus, the previous equation reduces to (5) with and given by (6a) (6b)…”

Up-frequency conversion in a two-resonant-wave high-gain free-electron-laser amplifier

“…This method can be of most practical interest in the genera tion of microwave or infrared radiation, when conventional input sources are not easily available. We envision the following set of parameters for a proof-of-principle experiment to generate radiation at 430 GHz with an input source at 43 GHz: A = 10 cm, N = 100, a = 2, waveguide dimensions, 10 x 50 mmz, electron beam energy, 9.6 MeV, I = 100 A, beam duration, 100 ps, input power at 43 GHz, 150 kW, output power at 430 GHz, 18 MW, efficiency, 2'. An extension to higher frequency is in principle possible but requires longer wigglers and beams.…”