Elements: Entity: Radiative General-Relativistic Particle-in-cell Toolkit for Extreme Plasma Astrophysics

围绕宇宙中最奇异的物体——黑洞和中子星——的极端等离子体现象的计算建模工作，在模拟的规模和复杂性方面，正以前所未有的速度增长。尽管如此，模拟框架的当前状态未能满足对该领域日益增长的兴趣。开发新的计算工具是本提案的主要议程。该奖项旨在开发一个开源、用户友好且易于访问的软件工具包，用于在各种平台（从笔记本电脑到高性能计算硬件，包括百亿亿次国家超级计算机和GPU集群）上研究极端等离子体的动态和辐射。该工具包的关键方面是易于使用，这对于教育该领域的新手至关重要，同时仍然提供足够高的可定制性，以促进要求更高的最新研究。该项目将在马里兰大学通过长达一学期或一年的项目为本科生和研究生提供培训，并将资助一名博士后学者，他将参与积极的发展过程。这个奖项导致了极端等离子体天体物理学的进步，这是等离子体物理研究的前沿，旨在了解天体物理致密物体附近的基本等离子体过程，其中带电粒子与产生的辐射的相互作用是重要的。为了描述感兴趣的系统，该团队开发了Entity，这是一种辐射广义相对论的细胞内粒子代码，可用于几种不同的网格几何（笛卡尔或柔性曲线坐标系，包括立方球网格，包括特殊和广义相对论）。实体将配备一个能够模拟所有天体物理学必需的qed等离子体相互作用过程的模块，以及一个使用半拉格朗日数值格式的连续介质求解器。在三年的资助期内，PI和合作者计划组织一系列训练营（包括在参与机构的现场培训，以及在更广泛的社区使用Zoom网络研讨会）。这些课程和讲座将涵盖极端等离子体天体物理学的各个方面，并侧重于与实体交互的基本实践。此外，本项目支持的博士后学者和研究生将接受广泛的专业、教育、公平、多样性和包容性培训，包括通过本项目工作获得的可转移技能。该项目推进了“宇宙之窗：多信使天体物理学时代”的目标，这是美国国家科学基金会未来投资的十大理念之一。该奖项由先进网络基础设施办公室颁发，由数学和物理科学理事会物理部的信息前沿物理项目联合支持。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。

The computational modeling efforts of extreme plasma phenomena around the most exotic objects in the Universe -- the black holes and the neutron stars -- are growing at an unprecedented rate both in terms of the scales of the simulations and in terms of their complexity. Nonetheless, the current state of the simulation frameworks fails to meet the growing interest in the field. The development of new computational tools is the primary agenda of this proposal. This award aims to produce an open-source, user-friendly, and easily accessible software toolkit used to investigate the dynamics and radiation of extreme plasmas on a variety of platforms varying from laptops to high-performance computing hardware, including the exascale national supercomputers and GPU clusters. The key aspect of the toolkit is its ease of use out-of-the-box, which is crucial for educating newcomers in the field, while still offering high-enough customizability to facilitate the more demanding state-of-the-art research. The project will provide training for undergraduate and graduate students through semester-long or year-long projects at the University of Maryland and will sponsor a postdoctoral scholar, who will be involved in the active development process.This award leads to advances in extreme plasma astrophysics -- a frontier in plasma physics research aiming at understanding fundamental plasma processes in the vicinity of astrophysical compact objects, where the interaction of charged particles with the produced radiation is important. To describe the systems of interest, the team develops Entity, a radiative general-relativistic particle-in-cell code, available in several different grid geometries (Cartesian or flexible curvilinear coordinate systems, including the cubed sphere grid, both special and general-relativistic). Entity is going to be equipped with a module capable of simulating all the astrophysically-necessary QED-plasma interaction processes, and a continuum solver using a semi-Lagrangian numerical scheme. During the three-year grant period, PI and collaborators plan to organize a set of training camps (both in-person at participating institutions and using Zoom webinars available to a broader community). These sessions and lectures will cover aspects of extreme plasma astrophysics and focus on basic practices for interacting with Entity. In addition, a postdoctoral scholar and graduate students supported by this project will receive extensive professional, educational, and equity, diversity, and inclusion training, including transferable skills acquired through work on this project. This project advances the objectives of "Windows on the Universe: the Era of Multi-Messenger Astrophysics", one of the 10 Big Ideas for Future NSF Investments.This award by the Office of Advanced Cyberinfrastructure is jointly supported by the Physics at the Information Frontier program in the Division of Physics within the Directorate for Mathematical and Physical Sciences.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.