  The goal of this paper is twofold: to explore the response of classical
charges to electromagnetic force at the level of unity in natural units and to
establish a criterion that determines physical parameters for which the related
radiation-reaction effects are detectable. In pursuit of this goal, the
Landau-Lifshitz equation is solved analytically for an arbitrary (transverse)
electromagnetic pulse. A comparative study of the radiation emission of an
electron in a linearly polarized pulse for the Landau-Lifshitz equation and for
the Lorentz force equation reveals the radiation-reaction dominated regime, in
which radiation-reaction effects overcome the influence of the external fields.
The case of a relativistic electron that is slowed down by a counter
propagating electromagnetic pulse is studied in detail. We further show that
when the electron experiences acceleration of order unity, the dynamics of the
Lorentz force equation, the Landau-Lifshitz equation and the
Lorentz-Abraham-Dirac equation all result in different radiation emission that
could be distinguished in experiment. Finally, our analytic and numerical
results are compared with those appearing in the literature.
