Laser-driven relativistic electron dynamics in a cylindrical plasma channel

摘要

The energy and trajectory of the electron,which is irradiated by a high-power laser pulse in a cylindrical plasma channel with a uniform positive charge and a uniform negative current,have been analyzed in terms of a single-electron model of direct laser acceleration.We find that the energy and trajectory of the electron strongly depend on the positive charge density,the negative current density,and the intensity of the laser pulse.The electron can be accelerated significantly only when the positive charge density,the negative current density,and the intensity of the laser pulse are in suitable ranges due to the dephasing rate between the wave and electron motion.Particularly,when their values satisfy a critical condition,the electron can stay in phase with the laser and gain the largest energy from the laser.With the enhancement of the electron energy,strong modulations of the relativistic factor cause a considerable enhancement of the electron transverse oscillations across the channel,which makes the electron trajectory become essentially three-dimensional,even if it is flat at the early stage of the acceleration.