Field polarization effect on electron dynamics in strong laser field

In this paper we present a comparison between the effects on electron dynamics by a linearly polarized and a circularly polarized field of an intense laser beam. Special attention is given to the vacuum laser acceleration scheme, also known as capture and acceleration scenario (CAS). It has been found that CAS phenomenon can occur in both polarized fields but there are differences. The CAS of a circularly polarized field exhibits axisymmetric feature, whereas CAS of a linearly polarized field can only be observed when electrons are injected nearly along the polarization plane. Given the same laser parameters (intensity, beam width), the maximum energy gained by the electrons from linearly polarized field is higher than that from circularly polarized field. Physical explanations based on the space distributions of the field amplitudes are described. We hope this study provides significant help to those designing experimental setup to verify CAS as well as to those developing laser accelerators of the future.