Multi-GeV cascaded laser wakefield acceleration in a hybrid capillary discharge waveguide

Based on a 6 cm-long two-segment hybrid capillary discharge waveguide, a multi-GeV electronbeam with energy up to 3.2 GeV and 9.7% rms energy spread was achieved in a cascaded laserwakefield acceleration scheme, powered by an on-target 210 TW laser pulse. The electron beamwas trapped in the first segment via ionization-induced injection, and then seeded into the secondsegment for further acceleration. The long-distance stable guiding of the laser pulse andsuppression of the dark current inside the second-segment capillary played an important role inthe generation of high-energy electron beams, as demonstrated by quasi-three-dimensionalparticle-in-cell simulations.

本研究基于一段长6 cm的两段式混合毛细管放电波导，在靶上210太瓦（TW）激光脉冲驱动的级联激光尾波场加速方案中，成功获得能量最高达3.2吉电子伏特（GeV）、均方根（rms）能量散度为9.7%的多吉电子伏特电子束。该电子束先通过电离诱导注入机制在第一段波导中被捕获，随后被注入第二段波导以进行进一步加速。准三维粒子网格（PIC）模拟结果证实，激光脉冲的长距离稳定导引，以及第二段毛细管内暗电流的抑制，对高能电子束的生成起到了重要作用。