Comparative study of inverse free-electron laser interaction based on helical and planar wiggler

Abstract

In an inverse free-electron laser (IFEL) scheme, a comparative study of single electron acceleration is carried out using a tightly focused Gaussian laser beam along with helical and planar wiggler fields. The effect of laser and wiggler field parameters is analyzed on single-electron dynamics and its acceleration. For the laser field descriptions, up to fifth-order corrections are included in the diffraction angle to study the effect of a tight laser pulse on electron acceleration. The Lorentz equation is solved using the fourth-order Runge Kutta method. Our numerical results indicate that considerable electron energy is attained for the helical and planar wiggler both for the optimal laser and wiggler field parameters, respectively. The effect of the laser field, its waist -size, and the effect of the wiggler field and its tapering along undulator length is studied for both helical and planar wiggler. The total electron energy gain for the helical wiggler case is 1.3 GeV due to the long interaction length while for the planar wiggler case, the electron energy gain is limited to 300 MeV only due to its shorter interaction length. This comparative analysis will certainly help us to understand the electron dynamics in IFEL and show the importance of helical wiggler over planar wiggler.