Classical theory of nonlinear Compton scattering

Summary from only given. The covariant dynamics of a single electron subjected to the electromagnetic field of an intense, ultrashort laser pulse in vacuum is studied theoretically at arbitrary intensities, in the context of the Dirac-Lorentz equation, which has long been suggested as a possible theory including the radiative reaction due to the electron self-interaction. A brief review of the Lorentz-Maxwell electrodynamics including canonical invariants and scattered light spectra is given, with a special emphasis on frequency modulation effects associated to the nonlinear relativistic Doppler shift induced by radiation pressure on the backscattered radiation. For circular polarization, an exact analytical expression for the full nonlinear spectrum is derived and presented. It is found that the scattering of coherent light by an electron describing a well-behaved trajectory can yield chaotic spectra when the laser ponderomotive force strongly modulates the electron's proper time. The Dirac-Lorentz equation is then derived and integrated numerically backward in time to ensure convergence towards the unique acausal solution satisfying the Dirac-Rohrlich asymptotic conditions (no runaway, law of inertia), and its consequences are investigated in terms of nonlinear Compton scattering. The relevance of this work to laser acceleration, as well as ongoing nonlinear Compton scattering experiments at SLAG and to the proposed /spl gamma/-/spl gamma/-collider is also discussed.