272 / 2023-04-24 12:56:21

Mechanism Studies for the Relativistic Attosecond Electron Bunches from Laser-Illuminated Nano-Targets

attosecond electron bunch,nano-target,ultra-fast laser

极端光下的基础物理学 > 粒子加速-I

Through comparing the finally obtained electronic distributions for three different target geometries under the illumination of a relativistic ultra-fast laser pulse, the results show that for a nano-foil target, limiting the transverse target size to a small value and increasing the longitudinal size to a certain extent can significantly improve the total electron number in a single bunch. Then in order to find a way to control the electron bunching process and the bunch emitting directions, we explored the mechanisms for the periodical generation of relativistic attosecond electron bunches when an ultra-intense, linearly polarized laser pulse grazing propagates along a nano-foil target. Through analyzing the sub-femtosecond electronic dynamics during the electron bunching process, it confirms that the charge separation field produced by the ions in the target plays a key role in the generation of the electron bunches. The electron initial energy can be directly determined by the intensity of the charge separation field. Then according to the different initial energy, all of the electrons in the target are divided into several bunches and accelerated within different laser half cycles. The final emitting direction is related to the electric field intensity of the corresponding laser half cycle. What's more, by adjusting the length of the nano-foil target, the number of attosecond radiation bunches generated by the electron bunches can be directly controlled. When the target length is short enough, an isolated attosecond electron bunch may be directly generated.