Ultrashort-duration relativistic electron beam accelerated by an intense laser

The self modulated laser wakefield regime, where the laser pulse duration is much longer than a plasma period is discussed. The field gradient of a plasma wave exceeds that of an RF linac by four orders of magnitude (E≥200 GV/m) and accelerates electrons with over 1-nc of charge per bunch in a low-emittance beam. At high laser power, the index of refraction in a plasma is demonstrated to vary with radius. A relativistically self-guided channel is found to increase the laser propagation distance, decrease the electron beam divergence, and increase the energy of the accelerated electrons. New concept for laser injection of electrons using the plasma itself as the cathode is also discussed.