The laser wakefield accelerator

A short (τL ∼ 2πωp-1 ∼1 picosec), high power (P ≥ 1015 W), single frequency laser pulse is capable of generating large amplitude (E ≥ 1 GeV/m) wakefields in a plasma. A correctly placed trailing electron bunch can be accelerated by the longitudinal electric field and focused by the transverse electric field of the wake plasma waves. The acceleration distance of this laser wakefield accelerator (LWFA) is most severely limited by the diffraction length of the laser pulse. However, at sufficiently high laser powers (P ≥ 17(ω/ωp)2 GW), relativistic optical guiding may be used to prevent the laser pulse from diffracting within the plasma. (author)