中文摘要：

研究表明,峰值强度为1022—1025W/cm2量级的圆偏振激光脉冲的有质动力场可以直接加速并产生GeV—TeV的单能电子束,其中被加速电子的能量与激光脉冲的峰值强度成线性定标关系.为了获得更高能量的电子束,通过对一维解析模型的分析得到：如果电子束在激光传播的方向上具一个初始能量E0,那么这种线性的定标关系可以被打破,被加速电子束最终的能量可以被放大E0倍.这是由于具有一定初始能量的电子束不容易被激光脉冲抛在后面,进而获得更高的加速距离.二维粒子模拟结果显示：当电子束的初始能量E0为MeV量级时这个方法是有效的,而当E0过大时这个方法失效.这是因为当电子的加速距离远大于激光脉冲的瑞利长度时,激光强度的衰减使得电子束的加速错过了最佳加速场.

英文摘要：

The earlier research showed that circularly polarized laser pulses with peak intensities in a range of 1022-1025 W/cm2 can directly accelerate and generate GeV-TeV monoenergetic electron beams with a linear energy scaling with the laser intensity. To obtain higher energy electron beams, a scheme is proposed to use an electron beam with an initial energy Eo along the laser propagation direction. This scheme can overcome the linear energy scaling with E0 = 0 obtained previously and enhance the beam energy by Eo folds. This is because an electron beam with an initial energy can move with the laser pulse together and therefore obtain a longer acceleration distance. Two-dimensional particle-in-cell simulation shows that this scheme is effective only for the electron beams initially with low energy on the order of MeV. With overhigh energy, electrons will miss the optimum acceleration field because the electron acceleration distance is much longer than the Rayleigh distance and the laser intensity is significantly attenuated.