An Innovative GPU-Optimized Multiscale Code for High-Fidelity Simulation of Collective Effects in Electron Beams

该奖项将导致开发一种创新的计算机代码，用于电子束的高保真模拟，借鉴并行计算机体系结构和应用数学的最新进展。 当电子束以接近光速的速度在加速器磁铁的作用下沿着弯曲的路径运动时，它们会发出明亮的紫外线或x射线。这种沿直线传播的辐射会赶上电子束，严重降低其实验实用性。 减轻这些破坏性影响的第一步是开发一个可靠的计算机代码，能够模拟这种光束自相互作用的物理过程。该项目将有助于制定这样一项守则。对于整个社会来说，这项研究是开发超亮光源的一个步骤，超亮光源是物理，生物，能源和医学科学发现和创新的重要工具。例如，它们允许科学家分析化学反应，分子结构，并提供开发新药的方法。 通过培养年轻的研究人员，该项目将增加美国急需的加速器科学家的数量，并在招募合格的女性和代表性不足的少数民族候选人方面做出相当大的努力。直接模拟二维和三维相干同步辐射（CSR）在效率和内存需求方面成本高昂。因此，目前的CSR代码采用各种近似，是不足以解决在许多现实情况下的基本物理。随着下一代光源设计的开始，现有CSR代码失效的这些情况将变得司空见惯。该项目将设计，基准测试和向社区传播一个全新的，多尺度的，粒子在细胞中的代码，用于建模CSR，优化运行在由图形处理单元（GPU）组成的并行计算平台上。该代码将利用铸造的小波基的问题的优点：（i）能够保留有关的动态信息的层次结构的尺度;（ii）通过阈值的小波系数去除数值噪声;和（iii）紧凑的表示数据和运营商，从而显着减少计算负荷。使用NVIDIA的CUDA框架，许多新代码的重要数值算法将被设计为在并行GPU平台上运行，算法和架构的成功匹配将导致代码的可扩展性。新代码将免费提供给社区，以支持对许多不同机器的建模。

This award will lead to development of an innovative computer code for high-fidelity simulation of electron beams, drawing on recent advances in parallel computer architectures and applied mathematics. When electron bunches traveling at nearly the speed of light are forced by accelerator magnets to traverse a curved path, they emit bright ultraviolet or x-ray radiation. This radiation traveling a straight path catches up with the electron beam and can severely degrade its experimental usefulness. The first step in mitigating these damaging effects is to develop a trustworthy computer code capable of simulating the physics of this beam self-interaction. This project will enable the development of such a code. For the society in general, this research is a step in developing ultra-bright light sources which are essential tools for discoveries and innovations in physical, biological, energy and medical sciences. For example, they allow scientists to analyze chemical reactions, molecular structures and provide ways to develop new drugs. By training young researchers, this project will increase the number of much-needed accelerator scientists in the nation and make considerable effort in recruiting qualified female and under-represented minority candidates.Direct simulation of coherent synchrotron radiation (CSR) in two and three dimensions is prohibitively costly in terms of efficiency and memory requirements. Consequently, the present CSR codes employ various approximations that are inadequate for resolving essential physics in many realistic situations. These situations where existing CSR codes fail will become commonplace as the design of next-generation light sources commences. This project will design, benchmark and disseminate to the community a fundamentally new, multiscale, particle-in-cell code for modeling CSR, optimized to run on a parallel computational platform consisting of graphical processing units (GPUs). The code will exploit advantages of casting the problem in wavelet basis: (i) ability to retain information about the dynamics over the hierarchy of scales; (ii) removal of numerical noise by thresholding of the wavelet coefficients; and (iii) compact representation of data and operators, resulting in significant reduction of the computational load. Using NVIDIA's CUDA framework, a number of new code's vital numerical algorithms will be designed to run on a parallel GPU platform, and the successful matching of the algorithms and architecture will lead to code's scalability. The new code will be freely available to the community to enable modeling of a number of different machines.