In the gas plasma an ultraintense laser pulse propagates leaving a wake with extremely high electric fields exceeding hundreds of GV/m. This peak electric field follows the laser at a phase velocity close to the speed of light, and it can trap, carry and accelerate plasma electrons to the relativistically high energies. The today's motion control of relativistic electrons with lasers provides an efficient and elegant way to map the space with ultra-intense electric field components, which in turn permits a unique improvement of the beam parameters.
(a) Setup for laser wakefield acceleration of electrons. (b) Artwork based on the Particle-In-Cell simulation of laser wakefield acceleration of electrons. (c) Measured electron energy spectrum with a magnetic dipole.