  The evolution of an electron beam colliding head-on with a strong plane-wave
field is investigated in the framework of strong-field QED including
radiation-reaction effects due to photon emission. Employing a kinetic approach
to describe the electron and the photon distribution it is shown that at a
given total laser fluence the final electron distribution depends on the shape
of the laser envelope and on the pulse duration, in contrast to the classical
predictions of radiation reaction based on the Landau-Lifshitz equation.
Finally, it is investigated how the pair-creation process leads to a nonlinear
coupled evolution of the electrons in the beam, of the produced charged
particles, and of the emitted photons.
