Laser electron acceleration on curved surfaces

Electron acceleration by relativistically intense laser beam propagating along a curved surface allows to split softly the accelerated electron bunch and the laser beam. The presence of a curved surface allows to switch an adiabatic invariant of electrons in the wave instantly leaving the gained energy to the particles. The efficient acceleration is provided by the presence of strong transient quasistationary fields in the interaction region and a long efficient acceleration length. The curvature of the surface allows to select the accelerated particles and provides their narrow angular distribution. The mechanism at work is explicitly demonstrated in theoretical models and experiments.