Excitation of accelerating plasma waves by counter-propagating laser beams

Generation of accelerating plasma waves using two counter-propagating laser beams is considered. Colliding-beam accelerator requires two laser pulses: the long pump and the short timing beam. We emphasize the similarities and differences between the conventional laser wakefield accelerator and the colliding-beam accelerator (CBA). The highly-nonlinear nature of the wake excitation is explained using both nonlinear optics and plasma physics concepts, Two regimes of CBA are considered: (i) the short-pulse regime, where the timing beam is shorter than the plasma period, and (ii) parametric excitation regime, where the timing beam is longer than the plasma period. Possible future experiments are also outlined.