Positron acceleration in plasma wakefield faces significant challenges, as the positron beam must be pre-generated and precisely coupled into the wakefield and, most critically, suffers from defocusing issues. Here we propose a scheme that utilizes laser-driven electrons to produce, inject, and accelerate positrons in a single setup. The high-charge electron beam from wakefield acceleration creates copious electron–positron pairs via the Bethe–Heitler process, followed by enormous coherent transition radiation due to the electrons’ exiting from the metallic foil. Simulation results show that the coherent transition radiation field reaches up to tens of GV m⁻¹, which captures and accelerates the positrons to cut-off energy of 1.5 GeV with energy peak of 500 MeV (energy spread ~ 24.3%). An external longitudinal magnetic field of 30 T is also applied to guide the electrons and positrons during the acceleration process. This proposed method offers a promising way to obtain GeV fast positron sources.

由于必须预先生成正电子束并将其精确耦合到尾波场中，因此等离子体尾波场中的正电子加速面临巨大挑战，最关键的是会遇到散焦问题。在这里，我们提出了一种利用激光驱动电子在单个设置中产生，注入和加速正电子的方案。来自尾波场加速的高电荷电子束通过贝特-海特勒过程产生大量的电子-正电子对，随后由于电子从金属箔中逸出而产生了巨大的相干过渡辐射。仿真结果表明，相干过渡辐射场可达数十GV m ^-1，它捕获并加速正电子，使其截止能量为1.5 GeV，能量峰值为500 MeV（能量扩散〜24.3％）。在加速过程中，还施加了30 T的外部纵向磁场以引导电子和正电子。该方法为获得GeV快速正电子源提供了有希望的方法。