Axial Magnetic-Field Effects in a Collective-Interaction Free-Electron Laser at Millimeter Wavelengths

Theoretical and Experimental Research on a Millimeter-Wavelength Free-Electron Laser

“…This will be no singularity in V, Ic at magnetoresonance, owing to transit time effects of the electron in the undulator. Simula- radiation is probably the same as that obtained by a group at Taking Ek =400 kV/cm, Bok -5 kG, Bo = 10 kG, we the Ecole Polytechnique' 6 in an experiment which used a calculate fl =0.4 in the drift section. Witness plates con.…”

“…and so it is not possible to predict the efficiency efficiency is improved using a tapered-period undulator on any given shot. in fact, the output pulse power showed [6], [7]. In this paper, we report data obtained from a appreciable variability, and the data we report represent Raman oscillator which has been operated with an undu-an average based on several shots.…”

“…-% ], 6 but unlike these experiments, it avoids magas the latter quickly saturates above the threshold field netoresonance (eB 0 /Wymc 2 k 0 -0.53) by use of stable ( 400 G). The dependence of the wavelength upon "group I" electron orbits.…”

“…This fact imposes stringent conditions on variayields Awcow, -I percent (1], [2]. Decreased pump ampli-tions of -in time (ZA7), since wi is a sensitive function of 7. tude reduces the spread of unstable frequencies [6] and Note that it is the pump frequency which varies during the narrows the bandwidth, while feedback permits power to grow FEL pulse; the scattered frequency is established by ambient over many bounce times of the cavity radiation. Low pump cavity radiation.…”

“…An beam, which means that the only surviving terms in (13) enhanced filling factor, in a resonator with fixed losses, are those with t = 1. We let C,,,(z) = C, (z) 6 e. , and will cause a reduction in the undulator field needed to ini-drop all subscripts e. We Equations (14) and (15) are coupled with (3) and (4) to -2 ,t"B2 ( t = -(V X J)., (9) form a complete set of equations. In oir model, the current density in (9) is purely transverse and does not excite where B,.…”