Ponderomotive electron–light interactions in multi-electron pulses

Abstract We investigate the impact of space-charge effects on the ponderomotive interaction between electron pulses and laser fields in the context of ponderomotive lenses. We present a numerical framework that self-consistently models both the ponderomotive electron–light interaction and the electron–electron Coulomb repulsion within multi-electron, ultrashort pulses. By comparing these simulations with a single-electron, wave-based description, we demonstrate that space-charge effects significantly degrade the performance of ponderomotive lenses for electron beam shaping and focusing. Our results show that this deterioration appears already at very low bunch charges, setting clear limits for the manipulation of dense electron pulses with ponderomotive optics.