论文标题
电子脉冲火车通过线性两极化的拉瓜仪激光束加速
Electron pulse train accelerated by a linearly polarized Laguerre-Gaussian laser beam
论文作者
论文摘要
线性极化的Laguerre-Gaussian（LP-LG）激光束具有扭曲指数$ L = -1 $的磁场结构，其场结构与常规线性极化高斯光束的场结构从根本上有所不同。靠近LP-LG梁的轴，纵向电场和磁场在横向组件上占主导地位。这种结构为在真空中加速电子提供了有吸引力的机会。使用三维粒子中的模拟显示，可以通过反射具有急剧密度梯度的等离子体的LP-LG激光来实现这种情况。模拟表明，在反射期间，一个600〜TW LP-LG激光束有效地将电子注射到光束中。接近激光轴的电子经历了纵向激光电场的延长纵向加速度。电子形成不同的单必须束，具有较小的差异角。最能量束中的能量为0.29 GEV。束费用为6〜PC，其持续时间为$ \ sim 270 $ 〜As。差异角度仅为\ dg {0.57}（10〜mrad）。通过使用线性极化而不是圆形极化的Laguerre-Gausian光束，我们的方案使在高功率激光器设施上实验证明电子加速变得更加容易。
A linearly polarized Laguerre-Gaussian (LP-LG) laser beam with a twist index $l = -1$ has field structure that fundamentally differs from the field structure of a conventional linearly polarized Gaussian beam. Close to the axis of the LP-LG beam, the longitudinal electric and magnetic fields dominate over the transverse components. This structure offers an attractive opportunity to accelerate electrons in vacuum. It is shown, using three dimensional particle-in-cell simulations, that this scenario can be realized by reflecting an LP-LG laser off a plasma with a sharp density gradient. The simulations indicate that a 600~TW LP-LG laser beam effectively injects electrons into the beam during the reflection. The electrons that are injected close to the laser axis experience a prolonged longitudinal acceleration by the longitudinal laser electric field. The electrons form distinct monoenergetic bunches with a small divergence angle. The energy in the most energetic bunch is 0.29 GeV. The bunch charge is 6~pC and its duration is $\sim 270$~as. The divergence angle is just \dg{0.57} (10~mrad). By using a linearly polarized rather than a circularly polarized Laguerre-Gausian beam, our scheme makes it easier to demonstrate the electron acceleration experimentally at a high-power laser facility.
