Continuation of Three-Dimensional Numerical Experiments on High-Intensity Particle and Laser Beam-Matter Interactions

该项目将使用计算机建模来研究和理解一种可能的新技术，用于开发紧凑型粒子加速器。粒子加速器是用于科学发现的最复杂、最昂贵的工具之一。它们被用来发现自然界中最基本的粒子，理解生物学的基本过程，探测和开发材料，以及治疗癌症。等离子体或电离气体有时被称为物质的第四态。当一个非常明亮的短脉冲或一个大电流的电子短脉冲通过等离子体时，就会产生尾流。尾流的波峰和波谷以接近光速的速度移动。像电子和正电子这样的带电粒子可以在尾流中冲浪，如果它们冲浪的时间很长，它们的能量就会不断增加。在等离子体尾流中，与现有的加速器相比，实现高能量所需的距离更短。使用美国最先进的超级计算机的复杂计算机模型可以模拟实验室实验中的情况。这有助于确定是否有必要建造一个大型而昂贵的实验设施来进一步研究这项新技术。这项研究还带来了新的发现，并更好地理解了等离子体中发生的基本过程。这可以为新技术和应用产生新概念。粒子池（PIC）方法将用于模拟强脉冲和短脉冲粒子束如何与等离子体相互作用。PIC方法跟踪等离子体中单个电子和离子通过其自一致产生的电场和磁场以及任何外部施加的场相互作用时的单个轨迹。该项目将研究强激光和粒子束如何产生非线性等离子体波尾流场，以及它如何从尾流场进行自调制。该项目还将探索如何将带电粒子束注入等离子体波中，以及粒子束的六维相空间在加速过程中如何演变。这些高度精确的模拟为理论思想和新概念提供了一个测试平台，也为指导正在进行和近期的实验提供了一种方法。高保真全尺寸建模还提供了一种方法，可以将参数外推到未来几年无法进行实验的制度中。PIC软件将继续发展，以便它能够继续有效地利用世界上最大和最快的计算机。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 use computer modeling to investigate and understand a possible new technology for developing compact particle accelerators. Particle accelerators are some of the most complex and expensive tools used for scientific discovery. They are used to discover the most fundamental particles in nature, to understand fundamental processes in biology, to probe and develop materials, and to treat cancer. A plasma, or ionized gas, is sometimes called the fourth state of matter. When a short pulse of very bright light or a short pulse of a high current of electrons are sent through a plasma a wake is created. The crests and troughs in this wake move near the speed of light. Charged particles such as electrons and positrons can then surf this wake, and if they surf for a long time their energy keeps increasing. In a plasma wake it takes a shorter distance to achieve high energies than in existing accelerators. Complex computer models using the nation's most advanced supercomputers can model what would happen in a laboratory experiment. This helps to determine if it makes sense to build a large and expensive experimental facility to further study this new technology. This research also leads to new discoveries and better understanding of fundamental processes that occur in plasmas. This can generate new concepts for new technologies and applications. A particle-in-cell (PIC) method will be used to simulate how intense and short-pulse particle beams interact with a plasma. The PIC method follows the individual trajectories of individual electrons and ions in the plasma as they interact through their self-consistently generated electric and magnetic fields and any externally applied fields. The project will study how the intense laser and particle beam creates a nonlinear plasma wave wakefield as well as how it self-modulates from the wakefield. The project will also explore how charged particle beams are injected into the plasma wave and how the six-dimensional phase space of the beam evolves as it is accelerated. These highly accurate simulations provide a testbed for theoretical ideas and new concepts, as well as a method for guiding ongoing and near term experiments. High-fidelity full-scale modeling also provides a means to extrapolate parameters into regimes that will not be accessible to experiments for years to come. The PIC software will continue to be developed so that it can continue to effectively utilize the largest and fastest computers in the world.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.