G8 Initiative: G8 Research Councils Initiative on Multilateral Research Funding

美国国家科学基金会授予普林斯顿大学的这一奖项资助美国研究人员参与一个项目，该项目是由八国集团研究理事会多边研究倡议通过跨学科应用软件计划为全球规模问题进行Exascale计算而竞争性选择的。这是美国国家科学基金会、加拿大国家科学和工程研究理事会（NSERC）、法国国家研究机构（ANR）、德国研究共同体（DFG）、日本科学促进会（JSPS）、俄罗斯基础研究基金会（RFBR）和英国研究理事会（RC-UK）之间的试点合作，支持在竞争基础上选定的合作研究项目，这些项目由来自至少三个伙伴国家的研究人员组成。轻核素的聚变形成了宇宙中能量释放的基础，有可能被利用和用作地球上清洁和可持续的能源供应。 为了建立开发聚变能所需的科学基础，一个关键的需要是及时开发磁约束聚变等离子体的综合高物理保真度预测模拟能力。 一个相关的中心物理学挑战是理解，预测和控制由磁约束热核等离子体中不可避免的空间变化（梯度）引起的不稳定性。一个后果是湍流波动（微湍流）的发生，它可以显着增加热量，粒子和动量的传输速率在约束磁场中的托卡马克装置，如ITER -一个数十亿美元的国际实验装置正在卡达拉什，法国和涉及的伙伴关系，7个政府代表超过一半的世界？的人口。 微湍流可以严重限制能量约束时间为一个给定的机器尺寸，因此它？的性能和经济可行性。了解并可能控制这些能量损失与实际聚变反应的自加热速率之间的平衡，是实现所需效率的关键，有助于确保未来聚变发电厂的实用性。 湍流输运的精确计算至关重要，只能通过先进的模拟来实现。目前的美国项目使用从头算粒子单元（PIC）全局（3D）代码来解决陀螺动力学理论的非线性方程，并已被证明可以扩展到超过100，000个处理器内核。根据计划，这些代码将部署在参与该八国集团项目的两个超级计算中心（美国的阿贡国家实验室和德国的Juelich超级计算中心），这些中心拥有最先进的HPC系统。 为了及时地产生具有尽可能高的物理保真度的模拟，预计在exascale计算将是必要的，以实现计算融合研究的最终目标？一种综合的预测模拟能力，该能力在与实际聚变能生产有关的制度中的实验中得到适当的验证。

This NSF award to Princeton University funds U.S. researchers participating in a project competitively selected by the G8 Research Councils Initiative on Multilateral Research through the Interdisciplinary Program on Application Software towards Exascale Computing for Global Scale Issues. This is a pilot collaboration among the U.S. National Science Foundation, the Canadian National Sciences and Engineering Research Council (NSERC), the French Agence Nationale de la Recherche (ANR), the German Deutsche Forschungsgemeinschaft (DFG), the Japan Society for the Promotion of Science (JSPS), the Russian Foundation for Basic Research (RFBR),and the United Kingdom Research Councils (RC-UK), supporting collaborative research projects selected on a competitive basis that are comprised of researchers from at least three of the partner countries.The fusion of light nuclides forms the basis of energy release in the universe, which can potentially be harnessed and used as a clean and sustainable supply of energy on Earth. In order to build the scientific foundations needed to develop fusion energy, a key need is the timely development of an integrated high-physics-fidelity predictive simulation capability for magnetically confined fusion plasmas. An associated central physics challenge is understanding, predicting, and controlling instabilities caused by the unavoidable spatial variations (gradients) in a magnetically-confined thermonuclear plasma. One consequence is the occurrence of turbulent fluctuations (microturbulence) which can significantly increase the transport rate of heat, particles, and momentum across the confining magnetic field in a tokamak device such as ITER -- a multi-billion dollar international experimental device being built in Cadarache, France and involving the partnership of 7 governments representing over half of the world?s population. Microturbulence can severely limit the energy confinement time for a given machine size and therefore it?s performance and economic viability. Understanding and possibly controlling the balance between these energy losses and the self-heating rates of the actual fusion reaction is key to achieving the efficiency needed to help ensure the practicality of future fusion power plants. Accurate calculations of turbulent transport are vitally important and can only be achieved through advanced simulations. The current U.S. project uses ab initio particle-in-cell (PIC) global (3D) codes to solve the nonlinear equations underlying gyrokinetic theory with excellent scaling to more than 100,000 processor cores having already been demonstrated. It is planned that these codes will be deployed at the two supercomputing centres involved in this G8 project (Argonne National Laboratory in the U.S. and Juelich Supercomputing Centre in Germany), where state-of-the-art HPC systems are operative. In order to move in a timely manner to producing simulations with the highest possible physics fidelity, it is expected that computing at the exascale will be necessary to achieve the ultimate goal of computational fusion research ? an integrated predictive simulation capability that is properly validated against experiments in regimes relevant for practical fusion energy production.