On the small-signal theory of stimulated Cherenkov emission in dielectric-lined waveguides

Abstract

The growth characteristics of a two-dimensional Cherenkov free-electron laser (CFEL) in the smallsignal low gain regime are studied for both single-electron and collective models. In the singleelectron regime, for a thick enough beam, we prove that the gain of the CFEL can be increased by a factor of 2 than that obtained for an infinitely thin electron beam. Thus, the Cherenkov laser should be considered as a hybrid longitudinal/transverse free-electron laser device in general. In the collective-regime, we demonstrate the damping effects of Coulomb collisions among electrons on the amplification characteristics of a Cherenkov laser. V C 2012 American Institute of Physics.

Analysis of Čerenkov free-electron lasers

“…In their analysis, they neglected the space charge effect and performed the calculations only in the low-gain regime. The analysis was further extended by several authors [5][6][7][8][9][10] by setting up the coupled Maxwell-Vlasov equations, and the growth rate was calculated. In most of the earlier analyses, the electron motion was assumed to be one dimensional in the presence of strong external static magnetic field [3][4][5]15].…”

The energy spread effects of an electron beam on the evolution of Cherenkov free-electron lasers

“…In equation (18), for comparison purposes, the coupling factor f c is added phenomenologically taking into account the effect of the spatial overlap between the beam and the evanescence field. Assuming the distribution of the electron beam is rectangular with thickness x s and the gap between the beam and the guide surface is ,…”

“…In equation (1), the factor C depends basically on the beam parameters and the mean free path d . m Several treatments have been adopted to determine the energy spread effects on the growth rate of the CFEL [18][19][20]. In most of these analyses, the linearized Vlasov equation has been used to compute the beam current.…”

Space-charge effects and gain in Cherenkov free-electron lasers

“…The presence of the positive ions in (or around) the electron beam greatly influences the electron relaxation. In the current quantum mechanical analysis, the electron relaxation process is viewed as a phase distortion in the electron wave and represents the Coulomb repulsion forces between electrons [29][30][31].…”