Ultra-intense lasers are a promising source of energetic ions for various applications. An interesting approach described in Ferri et al. [Commun. Phys. 2, 40 (2019)] argues from particle-in-cell simulations that using two laser pulses of half energy (half intensity) arriving with close to 45° angle of incidence is significantly more effective at accelerating ions than one pulse at full energy (full intensity). For a variety of reasons, at the time of this writing, there has not yet been a true experimental confirmation of this enhancement. In this paper, we perform 2D particle-in-cell simulations to examine if a millijoule class, $5\times {10}^{18}$ W cm⁻² peak intensity laser system could be used for such a demonstration experiment. Laser systems in this class can operate at a kHz rate which should be helpful for addressing some of the challenges of performing this experiment. Despite investigating a 3.5 times lower intensity than Ferri et al. [Commun. Phys. 2, 40 (2019)] did, we find that the double pulse approach enhances the peak proton energy and the energy conversion to protons by a factor of about three compared to a single laser pulse with the same total laser energy. We also comment on the nature of the enhancement and describe simulations that examine how the enhancement may depend on the spatial or temporal alignment of the two pulses.

中文翻译：

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双脉冲增强目标法向鞘加速的潜在演示实验的细胞内粒子建模

超强激光是用于各种应用的有前途的高能离子来源。Ferri等人描述了一种有趣的方法。[社区。物理。2 , 40 (2019)] 从细胞内粒子模拟中认为，使用两个半能量（半强度）激光脉冲以接近 45° 的入射角到达在加速离子方面比全能量的一个脉冲更有效（全强度）。由于各种原因，在撰写本文时，尚未对这种增强功能进行真正的实验确认。在本文中，我们执行 2D 细胞内粒子模拟来检查毫焦耳类，$5\times {10}^{18}$W cm ^-2峰值强度激光系统可用于此类演示实验。此类激光系统可以以 kHz 速率运行，这应该有助于解决执行此实验的一些挑战。尽管调查的强度比 Ferri等人低 3.5 倍。[社区。物理。2 , 40 (2019)] 确实如此，我们发现与具有相同总激光能量的单个激光脉冲相比，双脉冲方法将峰值质子能量和向质子的能量转换提高了大约三倍。我们还评论了增强的性质并描述了检查增强如何取决于两个脉冲的空间或时间对齐的模拟。