Dual-Frequency-Inverse Free-Electron Laser Accelerator With Bi-Period Undulator

In this article, we have examined the effect of bi-period undulator magnetic field on inverse free-electron laser (IFEL) accelerator. The IFEL equations are derived and synchrotron radiation losses are included in the analysis. The accelerator acts as a dual channel when the phase between the two undulator field components
$\phi _{2}$
is equal to
$\pi $
and as one period for
$\phi _{2} =\pi /2$
. Both the IFEL accelerator parameters accelerating gradient and saturation length are affected by varying
$\phi _{2} $
.