Energetic helical electron-bunch generation driven by a light spring wakefield

This paper investigates the interaction between a light spring pulse and a gaseous plasma, resulting in the formation of a three-dimensional helical wakefield and the generation of a high-energy helical electron beam carrying orbital angular momentum (OAM).During this process, the ponderomotive force of the LS expels background electrons along helical trajectories, forming a unique "spring-like" bubble structure.Within this bubble, not only does a longitudinal acceleration field exist, imparting longitudinal momentum to the injected electrons, but also the synergistic interplay between the azimuthal electric and radial focusing fields endows the trapped and accelerated electrons with significant OAM.Most importantly, the OAM and helical structure of the electron beam are well-preserved even after propagation into the vacuum.This paper reveals that the spring-like wakefield driven by an LS pulse serves as a novel acceleration structure.This creates a new pathway for the direct generation of highenergy electron beams that carry OAM and exhibit three-dimensional structural characteristics.Furthermore, it expands the potential application prospects of this beams in advanced fields such as radiation sources and the detection of materials sensitive to angular momentum.