Enhanced acceleration of injected electrons in a laser-beat-wave-induced plasma channel

Laser-plasma-based particle accelerators are of great interest because a plasma accelerating structure can sustain very strong electric fields induced by a high-power laser beam [1]. These accelerators utilize a relativistic plasma wave (RPW) with a phase velocity close to the speed of light for charged particle acceleration to high energies. Acceleration gradients of 1‐3 GeV=m over 10 mm and 100 GeV=m over a 2m minteraction length have been reported for plasma beat wave accelerators (PBWA) [2,3] and self-modulated laser-wakefield accelerators (SM-LWFA) [4,5], respectively. Even though the accelerating gradients in laser-driven plasma accelerators can be very large, the overall energy gain will be modest if the length is short. In a laser-plasma accelerator the interaction length ����������������