论文标题
克服多脉冲激光器韦克菲尔德加速度的脱落极限
Overcoming the dephasing limit in multiple-pulse laser wakefield acceleration
论文作者
论文摘要
激光驱动的等离子体Wakefield加速度的电场比传统的射频腔高的数量级，但是通过在激光组速度下游行的超偏好性电子束和韦克菲尔德之间的限制，能量增益受到限制。我们提出了一种在单个等离子体阶段克服该极限的方法。可以通过调节密度曲线来控制飞机脉冲列车后面的韦克场的振幅。这创建了一系列的共振激光 - 血浆加速器部分和非谐波漂移截面，其中韦克菲尔德消失了，电子的反射。具有四个2.5TW激光脉冲的二维粒子模拟会产生50mev电子的能量增益，这是从均匀等离子体中获得的四倍。尽管Laser Red-Shift阻止了井喷状态下的运行，但该技术为可用激光功率限制为线性态度的加速器提供了增加的能量增益。这与能够以高重复速率运行的激光X射线源尤其重要，这是高度追捧的。
The electric field in laser-driven plasma wakefield acceleration is orders of magnitude higher than conventional radio-frequency cavities, but the energy gain is limited by dephasing between the ultra-relativistic electron bunch and the wakefield, which travels at the laser group velocity. We present a way to overcome this limit within a single plasma stage. The amplitude of the wakefield behind a train of laser pulses can be controlled in-flight by modulating the density profile. This creates a succession of resonant laser-plasma accelerator sections and non-resonant drift sections, within which the wakefield disappears and the electrons rephase. A two-dimensional particle-in-cell simulation with four 2.5TW laser pulses produces a 50MeV electron energy gain, four times that obtained from a uniform plasma. Although laser red-shift prevents operation in the blowout regime, the technique offers increased energy gain for accelerators limited to the linear regime by the available laser power. This is particularly relevant for laser-plasma x-ray sources capable of operating at high repetition rates, which are highly sought after.
