  This work is dedicated to the study of radiation reaction signatures in the
framework of classical and quantum electrodynamics. Since there has been no
distinct experimental validation of radiation reaction and its underlying
equations so far and its impact is expected to be substantial for the
construction of new experimental devices, e.g., quantum x-free electron lasers,
a profound understanding of radiation reaction effects is of special interest.
Here, we describe how the inclusion of quantum radiation reaction effects
changes the dynamics of ultra-relativistic electron beams colliding with
intense laser pulses significantly. Thereafter, the angular distribution of
emitted radiation is demonstrated to be strongly altered in the quantum
framework, if in addition to single photon emission also higher order photon
emissions are considered. Furthermore, stimulated Raman scattering of an
ultra-intense laser pulse in plasmas is examined and forward Raman scattering
is found to be significantly increased by the inclusion of radiation reaction
effects in the classical regime. The numerical simulations in this work show
the feasibility of an experimental verification of the predicted effects with
presently available lasers and electron accelerators.
