  The next few years will see next-generation high-power laser facilities (such
as the Extreme Light Infrastructure) become operational, for which it is
important to understand how interaction with intense laser pulses affects the
bulk properties of a relativistic electron beam. At such high field
intensities, we expect both radiation reaction and quantum effects to play a
significant role in the beam dynamics. The resulting reduction in relative
energy spread (beam cooling) at the expense of mean beam energy predicted by
classical theories of radiation reaction depends only on the energy of the
laser pulse. Quantum effects suppress this cooling, with the dynamics
additionally sensitive to the distribution of energy within the pulse. Since
chirps occur in both the production of high-intensity pulses (CPA) and the
propagation of pulses in media, the effect of using chirps to modify the pulse
shape has been investigated using a semi-classical extension to the
Landau--Lifshitz theory. Results indicate that even large chirps introduce a
significantly smaller change to final state predictions than going from a
classical to quantum model for radiation reaction, the nature of which can be
intuitively understood.
