High-intensity scattering processes of relativistic electrons in vacuum and their relevance to high-energy astrophysics

The recent advent of ultra-short pulse, high-intensity lasers, together wit h advances in other novel technologies, such as high-gradient radiofrequenc y photoinjectors, have afforded researchers the possibility to simulate ast rophysical conditions in the laboratory. Laser-produced plasmas have been s uccessfully used to simulate astrophysical plasmas and supernovae in the la boratory for several years. Now, femtosecond laser systems operating in the terawatt to petawatt range are available, as are synchronized relativistic electron bunches with subpicosecond durations and terahertz bandwidths. Wi th these tools, experiments have been conducted to study phenomena related to supernova explosions, stellar winds, solar coronae, cosmic rays, planeta ry and celestial matter, and interstellar plasmas. Other experiments have b een proposed to investigate Unruh radiation, as well as ponderomotive scatt ering, which can accelerate electrons in vacuum to relativistic energies us ing the extremely high gradients in a three-dimensional laser focus. The no nlinear Doppler shift induced by ultrarelativistic radiation pressure is sh own to yield complex nonlinear Compton backscattered spectra. Finally, stro ng radiative corrections are expected when the Doppler-upshifted laser wave length approaches the Compton scale. These are discussed within the context of high-held classical electrodynamics, a new discipline borne out of the aforementioned innovations.