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。超强激光正在给等离子体物理领域带来革命性的变化，并导致了许多令人兴奋的应用。其中一种应用包括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治疗肿瘤等各种应用，而不会损害周围组织，也不会产生用于核物理研究的中子。虽然使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使用一阵风在湖上移动帆船更具挑战性，但在如此巨大的激光强度下，激光与目标相互作用的细节相当复杂。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方向性。这一努力将通过研究一种新的概念-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-它利用由多拍瓦(MPW)激光脉冲推动的非均匀厚度的超薄固体目标。通过利用边缘附近较薄的靶，LILA潜在地实现了离子束的同时加速和聚焦，同时保持了它的小角度发散。这种会聚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、纳米制造和在一些主要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，包括对集体激光等离子体不稳定性进行建模、了解包含多种离子物种的准中性等离子体的行为、优化和制造设计者的目标轮廓，以及降低光束的可实现发射度。将设计和进行利用现有和即将使用的激光设备进行的原则验证实验。将在欧洲和亚洲的几个MPW设施建立广泛的国际合作，以实现该项目的关键目标。其智力优势包括开发新的计算工具，以进一步了解MPW激光与结构化固体目标的相互作用，它们的稳定性，以及对广泛应用的适用性。更广泛的影响包括未来紧凑型基于激光的相对论离子加速器的开发，以及培训下一代科学家，包括研究生和本科生。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.