The efficient injection of electrons into a propagating relativistic laser pulse with normalized vector potential a ₀ ∼ 2 is demonstrated numerically and experimentally in a thin plasma layer with density 0.15–0.3 of the critical value. The injection is due to the wavebreaking of parametric plasma waves. The trapped particles gain multi-MeV (up to 20 MeV) energies by the direct laser acceleration in the plasma channel formed by the laser pulse in the lower density plasma tail. Numerical calculations were supported by experiments with micron-scale films pre-evaporated by an additional nanosecond laser pulse and a TW femtosecond laser facility. The experimentally observed bunch of electrons with energy above 1.6 MeV had a divergence of ∼0.05 rad and charge of ∼50 pC measured with photoneutron Be(g,n) reaction.

将电子有效地注入到归一化矢量势为 _0的相对论传播激光脉冲中数值2和实验2在临界密度为0.15-0.3的薄等离子体层中得到证明。注入归因于参量等离子体波的破裂。被捕获的粒子通过在低密度等离子体尾部中的激光脉冲形成的等离子体通道中直接进行激光加速而获得多MeV（最高20 MeV）的能量。通过额外的纳秒激光脉冲和TW飞秒激光设备预蒸发的微米级薄膜的实验，为数值计算提供了支持。实验观察到的能量大于1.6 MeV的电子束的发散度约为0.05 rad，用光中子Be（g，n）反应测得的电荷约为50 pC。