The multiphoton cross sections verse the number of exchanged photons in the laser-assisted processes of electron scattering with impact energy of T i = mc 2 = 0.511 MeV . The scattering angels are (a) θ = 1 ° , (b) θ = 90 ° , and (c) θ = 180 ° . The laser field is linearly polarized along the incident direction of the electron, the field intensity is ε 0 = 0.01 = 5.14 × 10 7 V · cm − 1 , and the photon energy ℏ ω = 1.17 eV .