Polarization effects in collisions between very intense laser beams and relativistic electrons

Abstract

The interaction between laser and relativistic electron beams is a promising source of very energetic X rays. We present an accurate model for the collisions between very intense linearly polarized laser beams, corresponding to relativistic parameters of the order of unity or greater, and electrons having energies up to 100 MeV. Our approach uses only one approximation, namely it neglects the radiative corrections. We consider the two cases in which the laser field polarization is either perpendicular or parallel to the plane defined by the directions of propagation of the laser beam and electron beam, and calculate accurately the properties of the σ and π polarized scattered beams. The angle between the directions of the laser and electron beams, denoted by θ L , is allowed to have arbitrary values, so that the widely analyzed 180°and 90°geometries, in which the two beams collide, respectively, head on and perpendicularly, are particular cases. We prove that the polarization properties of the scattered beam depend on the angle θ L . By varying this angle, the polarization of the scattered beam can be varied between the two limit configurations in which the electromagnetic field of the scattered beam is σ or π polarized with respect to the scattering plane. Our theoretical results are in good agreement with experimental results published in literature. Our model shows that current technologies can be used to produce hard harmonics of the scattered radiations. These harmonics can have relatively high intensities comparable to the intensities of the first harmonics, and energies higher than 1 MeV. Our results lead to the possibility to realize an adjustable photon source with both the energy and polarization of the scattered radiations accurately controlled by the value of the θ L angle.

Accurate calculation of radiation damping parameters in the interaction between very intense laser beams and relativistic electron beams

“…In previous papers (Popa, 2011;2012), we proved that the electrical field which results from the Liènard-Wiechert relation, due to the motion of the electron in the laser field, is a periodic function of only one variable, that is, the phase of the incident electromagnetic field. This property simplifies significantly the calculation model for the generation of hard radiations, in interactions between very intense laser fields and particles.…”

“…The solution of the system of equations (33)-(35), which leads to the expressions of β ′ x ′ , β ′ y ′, γ ′ , dγ ′ /dt ′ and dη/dt ′ , is presented in our previous papers (Popa, 2011;2012). For the completeness of the presentation, we will give it briefly below.…”

“…We use an algorithm similar to that presented in the papers by Popa (2011;2012) to calculate the ratio between the damping energy and the average kinetic energy, and the ratio between the damping force and external force. This algorithm has the following stages.…”

Frequency scaling law for nonlinear Compton and Thomson scattering: Relevance of spin and polarization effects

“…(For more works on polarization effects in Thomson scattering, we refer the reader to Refs. [28,39,40,49]; the polarization effects in Compton scattering were analyzed more closely in Refs. [36,45,55].)…”

“…As we already mentioned, many of the existing calculations on nonlinear Compton and Thomson scattering treated the driving laser beam as a monochromatic plane wave (see, for instance, Refs. [16,19,[29][30][31][32][33][34][35][36][37][38][39][40]). Few works on Compton scattering beyond this approximation can be found in literature [25][26][27][28][41][42][43][44][45].…”