Generation of highly collimated monoenergetic relativistic ion beams is one of the most challenging and promising areas in ultraintense laser-matter interactions because of the numerous scientific and technological applications that require such beams. We address this challenge by introducing the concept of laser-ion lensing and acceleration. Using a simple analogy with a gradient-index lens, we demonstrate that simultaneous focusing and acceleration of ions is accomplished by illuminating a shaped solid-density target by an intense laser pulse at $\sim {10}^{22}\mathrm{W}/{\mathrm{cm}}^2$ intensity, and using the radiation pressure of the laser to deform or focus the target into a cubic micron spot. We show that the laser-ion lensing and acceleration process can be approximated using a simple deformable mirror model and then validate it using three-dimensional particle-in-cell simulations of a two-species plasma target composed of electrons and ions. Extensive scans of the laser and target parameters identify the stable propagation regime where the Rayleigh-Taylor-like instability is suppressed. Stable focusing is found at different laser powers (from a few to multiple petawatts). Focused ion beams with the focused density of order ${10}^{23}{\mathrm{cm}}^{-3}$, energies in access of 750 MeV, and energy density up to $2\times {10}^{13}\mathrm{J}/{\mathrm{cm}}^3$ at the focal point are predicted for future multipetawatt laser systems.

中文翻译：

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激光离子透镜和加速器

高度准直的单能相对论离子束的产生是超强激光物质相互作用中最具挑战性和最有前途的领域之一，因为需要此类束的众多科学技术应用。我们通过引入激光离子透镜化和加速的概念来应对这一挑战。使用一个简单的类比与梯度折射率透镜，我们证明了离子的同时聚焦和加速是通过用强激光脉冲照亮一个成形的固体密度目标来实现的。$〜{10}^{22}\mathrm{w\; ^}/{\mathrm{厘米}}^2$强度，并利用激光的辐射压力将目标变形或聚焦到立方微米的光斑中。我们表明，可以使用简单的可变形反射镜模型对激光离子的透镜化和加速过程进行近似，然后使用由电子和离子组成的两种等离子体靶的三维粒子模拟来对其进行验证。广泛的激光扫描和目标参数确定了稳定的传播机制，其中抑制了瑞利-泰勒式不稳定性。在不同的激光功率下（从几皮瓦到几皮瓦），可以找到稳定的聚焦。聚焦离子束，聚焦密度为阶数${10}^{23}{\mathrm{厘米}}^{-3}$，能量可达750 MeV，能量密度高达 $2\times {10}^{13}\mathrm{Ĵ}/{\mathrm{厘米}}^3$ 预计未来的多匹瓦激光系统将处于焦点。