Interaction of Ultra-Intense Laser Pulses with Structured Targets in the Multi-Petawatt Regime

这个项目将研究高功率激光加速粒子的新概念。超强激光正在彻底改变等离子体物理领域，并导致了许多令人兴奋的应用。其中一个应用是将离子束加速到接近光速的速度。这种相对论光束可以用于多种用途，如治疗肿瘤而不损害周围组织或为核物理学研究产生中子。虽然利用超强激光脉冲的辐射压力来加速固体密度目标的基本想法似乎并不比利用一股风在湖面上移动一艘帆船更具挑战性，但在如此巨大的激光强度下激光与目标相互作用的细节是相当复杂的。许多物理过程，包括带电目标的不稳定性和爆炸，共同降低了加速离子的能量和指向性。这项工作将通过研究一种新概念——激光离子透镜和加速器（LILA）——来克服激光驱动离子加速的挑战，这种新概念利用了一个厚度不均匀的超薄固体目标，由多佩瓦（MPW）激光脉冲推动。通过利用边缘附近更薄的目标，LILA有可能同时加速和聚焦离子束，同时保持其小角发散。这种聚合等离子体流的物理性质以前还没有被研究过。通过理论建模、纳米制造和在一些一流激光设备上的实验相结合，该项目将解决一系列独特的挑战，包括模拟集体激光等离子体的不稳定性，理解含有多种离子的准中性等离子体的行为，优化和制造设计目标轮廓，以及降低光束的可实现发射度。利用现有的和即将到来的激光设备，将设计和进行原理验证实验。将在欧洲和亚洲的几个MPW设施建立广泛的国际合作，以实现该项目的主要目标。智力上的优点包括开发新的计算工具，以进一步了解MPW激光与结构固体目标的相互作用，其稳定性和广泛应用的适用性。更广泛的影响包括未来紧凑型激光相对论加速器的发展，以及培养下一代科学家，包括研究生和本科生。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This project will investigate a novel concept of particle acceleration by high power lasers. Ultra-powerful lasers are revolutionizing the field of plasma physics and leading to a number of exciting applications. One such application involves accelerating ion beams to velocities approaching the speed of light. Such relativistic beams can be used for applications as varied as treating tumors without damaging the surrounding tissues or producing neutrons for nuclear physics studies. While the basic idea of using radiative pressure of ultra-intense laser pulse to accelerate solid density targets may appear to be not much more challenging than using a blast of wind to move a sailboat across a lake, the details of laser-target interactions at such enormous laser intensities is quite complex. Many physical processes, including instabilities and explosions of electrically-charged targets, conspire to reduce the energy and directivity of the accelerated ions.This effort will overcome challenges to laser-driven ion acceleration by investigating a novel concept – Laser-Ion Lens and Accelerator (LILA) – that utilizes an ultra-thin solid target with non-uniform thickness propelled by a multi-petawatt (MPW) laser pulse. By utilizing targets that are thinner near the edge, LILA potentially enables simultaneous acceleration and focusing of the ion beam while preserving its small angular divergence. Physical properties of such converging plasma flows have not been previously investigated. Through the combination of theoretical modeling, nanofabrication, and experimentation at some of the premier laser facilities, this project will address a unique set of challenges, including modeling collective laser-plasma instabilities, understanding the behavior of quasi-neutral plasmas containing multiple ion species, optimization and fabrication of the designer target profiles, and reducing the achievable emittance of the beam. Proof-of principle experiments utilizing the existing and upcoming laser facilities will be designed and carried out. Extensive international collaborations at several MPW facilities in Europe and Asia will be established to achieve the key objectives of this project. The intellectual merit consists of developing novel computational tools for furthering our understanding of MPW laser interactions with structured solid targets, their stability, and suitability for a wide range of applications. The broader impacts include development of future compact laser-based relativistic ion accelerators, as well as training the next generation of scientists, including graduate and undergraduate students.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.