Matter can be transferred into energy and the opposite transformation is also possible by use of high-power lasers. A laser pulse in plasma can convert its energy into γ-rays and then e − e + pairs via the multi-photon Breit-Wheeler process. Production of dense positrons at GeV energies is very challenging since extremely high laser intensity ~1024 Wcm−2 is required. Here we propose an all-optical scheme for ultra-bright γ-ray emission and dense positron production with lasers at intensity of 1022–23 Wcm−2. By irradiating two colliding elliptically-polarized lasers onto two diamondlike carbon foils, electrons in the focal region of one foil are rapidly accelerated by the laser radiation pressure and interact with the other intense laser pulse which penetrates through the second foil due to relativistically induced foil transparency. This symmetric configuration enables efficient Compton back-scattering and results in ultra-bright γ-photon emission with brightness of ~1025 photons/s/mm2/mrad2/0.1%BW at 15 MeV and intensity of 5 × 1023 Wcm−2. Our first three-dimensional simulation with quantum-electrodynamics incorporated shows that a GeV positron beam with density of 2.5 × 1022 cm−3 and flux of 1.6 × 1010/shot is achieved. Collective effects of the pair plasma may be also triggered, offering a window on investigating laboratory astrophysics at PW laser facilities.
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机译:物质可以转化为能量,通过使用大功率激光器也可以实现相反的转化。等离子体中的激光脉冲可以将其能量转换为γ射线,然后通过多光子Breit-Wheeler过程生成e - sup> e + sup>对。由于需要极高的〜10 24 sup> Wcm -2 sup>激光强度,因此在GeV能量下产生致密的正电子非常具有挑战性。在这里,我们提出了使用10 22–23 sup> Wcm −2 sup>强度的激光产生超亮γ射线并产生致密正电子的全光学方案。通过将两个碰撞的椭圆偏振激光照射到两个菱形碳箔上,一个箔的焦点区域中的电子在激光辐射压力的作用下迅速加速,并且由于相对论引起的箔透明性而与穿过第二箔的另一个强激光脉冲相互作用。 。这种对称配置可实现高效的康普顿反向散射,并产生超亮的γ光子发射,亮度约为10 25 sup>光子/ s / mm / s 2 sup> / mrad 15 MeV时2 sup> /0.1%BW,强度为5 intensity×10 23 sup> Wcm −2 sup>。我们的第一个包含量子电动力学的三维模拟显示,GeV正电子束的密度为2.5×10 22 sup> cm -3 sup>,通量为1.6×10 达到10 sup> / shot。等离子体对的集体效应也可能被触发,为研究PW激光设施的实验室天体物理学提供了一个窗口。
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