Vranic Marija, Klimo Ondrej, Korn Georg, Weber Stefan
GoLP/Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, 1049-001, Lisbon, Portugal.
Institute of Physics of the CAS, ELI-Beamlines Project, Na Slovance 2, Prague, 182 21, Czech Republic.
Sci Rep. 2018 Mar 16;8(1):4702. doi: 10.1038/s41598-018-23126-7.
The new generation of laser facilities is expected to deliver short (10 fs-100 fs) laser pulses with 10-100 PW of peak power. This opens an opportunity to study matter at extreme intensities in the laboratory and provides access to new physics. Here we propose to scatter GeV-class electron beams from laser-plasma accelerators with a multi-PW laser at normal incidence. In this configuration, one can both create and accelerate electron-positron pairs. The new particles are generated in the laser focus and gain relativistic momentum in the direction of laser propagation. Short focal length is an advantage, as it allows the particles to be ejected from the focal region with a net energy gain in vacuum. Electron-positron beams obtained in this setup have a low divergence, are quasi-neutral and spatially separated from the initial electron beam. The pairs attain multi-GeV energies which are not limited by the maximum energy of the initial electron beam. We present an analytical model for the expected energy cutoff, supported by 2D and 3D particle-in-cell simulations. The experimental implications, such as the sensitivity to temporal synchronisation and laser duration is assessed to provide guidance for the future experiments.
新一代激光装置有望产生峰值功率为10 - 100拍瓦的短（10飞秒 - 100飞秒）激光脉冲。这为在实验室中研究极端强度下的物质提供了契机，并开启了探索新物理的大门。在此，我们提议用多拍瓦激光以正入射方式散射来自激光等离子体加速器的吉电子伏特级电子束。在这种配置下，既能产生又能加速电子 - 正电子对。新粒子在激光焦点处产生，并在激光传播方向上获得相对论动量。短焦距是一个优势，因为它能使粒子在真空中以净能量增益从焦点区域射出。通过这种设置获得的电子 - 正电子束发散度低、准中性且在空间上与初始电子束分离。这些粒子对可达到多吉电子伏特的能量，且不受初始电子束最大能量的限制。我们提出了一个关于预期能量截止的解析模型，并得到了二维和三维粒子模拟的支持。评估了诸如对时间同步和激光持续时间的敏感度等实验影响因素，为未来实验提供指导。
