HIGH-INTENSITY SCATTERING PROCESSES OF RELATIVISTIC ELECTRONS IN VACUUM

Recent advances in novel technologies such as chirped pulse amplificat ion and high gradient rf photoinjectors make it possible to study expe rimentally the interaction of relativistic electrons with ultrahigh in tensity photon fields. Femtosecond laser systems operating in the TW-P W range are now available, as well as synchronized relativistic electr on bunches with subpicosecond durations and THz bandwidths. Ponderomot ive scattering can accelerate these electrons with extremely high grad ients in a three-dimensional vacuum laser focus. The nonlinear Doppler shift induced by relativistic radiation pressure in Compton backscatt ering is shown to yield complex nonlinear spectra which can be modifie d by using temporal laser pulse shaping techniques. Colliding lasers p ulses, where ponderomotive acceleration and Compton backscattering are combined, could also yield extremely short wavelength photons. Finall y, strong radiative corrections are expected when the Doppler-upshifte d laser wavelength approaches the Compton scale. These are discussed w ithin the context of high field classical electrodynamics, a new disci pline borne out of the aforementioned innovations. (C) 1998 American I nstitute of Physics.