Theory of the Laser Wake-Field Accelerator Revisited: Wake Overtaking, Localized Spectrum and Ponderomotive Acceleration

摘要

The electron and positron acceleration in the first cycle of a laser-drivenwakefield is investigated. Separatrices between different types of the particlemotion (confined, reflected by the wakefield or ponderomotive potential andtransient) are demonstrated. The ponderomotive acceleration is negligible forelectrons but is substantial for positrons. An electron bunch, injected asquasi-monoenergetic, acquires a localized energy spectrum with a cut-off at themaximum energy.