INSPIRE: STAR: Scalable toolkit for Transformative Astrophysics Research

该INSPIRE奖的部分资金来自数学和物理科学理事会天文科学部的恒星天文学和天体物理学计划，计算机和信息科学与工程理事会计算和通信基础部的软件和硬件基础计划以及信息技术计划，该奖项将支持一项大规模的计算工作，以模拟白色矮星的分裂和合并。 主要目标是包括比当前模型显着改进的物理现实主义。 白色矮星是像太阳这样恒星演化的低质量终点。 其中许多是在近距离双星系统中发现的，众所周知，这种近距离双星将在10亿到100亿年的时间尺度上合并。 白色矮星的合并最近被认为是Ia型超新星的一个重要的额外产生通道，Ia型超新星是宇宙膨胀的最重要的探测器。 合并过程和随后的爆炸需要同时模拟大量的物理过程，包括磁流体动力学、核合成、辐射输运和快速变化的引力场。 这些不同的过程有着不同的自然长度、时间和密度尺度，而在当前的程序中，还无法实现对恒星合并进行高度逼真的模拟所需的复杂程度，该项目需要计算技术的进步。 其中一个关键目标是提高大规模并行体系结构上的多物理场模拟的性能，这是目前受到数据分布和资源分配的规模和开销问题的限制。 这项工作将探讨开销和并行性之间的各种权衡，并将使改进的战略，以使更有效和更可扩展的计算天体物理和其他问题。的计算技术超越了恒星合并的直接问题。 恒星天体物理学中的一些相关问题也需要综合处理流体动力学，动态重力，热和辐射传输，以及核能发电。 该小组预计，最大的直接影响将出现在超新星爆炸建模，各种类型恒星的合并以及潮汐效应和旋转重要时的恒星演化领域。

This INSPIRE award is partially funded by the Stellar Astronomy and Astrophysics Program in the Division of Astronomical Sciences in the Directorate for Mathematical and Physical Sciences, by the Software and Hardware Foundations Program and the Information Technology Program in the Division of Computing and Communication Foundations in the Directorate for Computer and Information Science and Engineering, and by the Experimental Program to Stimulate Competitive Research in the Office of Integrative Activities.This award will support a large-scale computational effort to model the disruption and merger of white dwarf stars. The major goal is to include significantly improved physical realism than in current models. White dwarf stars are the low-mass endpoints of stellar evolution for stars like the Sun. Many of these are found in close binary systems, and it is well known that such close binaries will merge on time scales of 1 to 10 billion years. White dwarf mergers have recently been proposed as an important additional production channel for Type Ia supernovae, which are the most important probes of the expansion of the universe. The merger process and subsequent explosion requires that a large number of physical processes all be modeled at once, including magnetohydrodynamics, nucleosynthesis, radiative transport, and rapidly-changing gravitational fields. These various processes have quite different natural length, time, and density scales, and the level of complexity required for highly realistic modeling of stellar mergers is not achievable in current codes.The project will require advances in computational techniques. One of the key goals is to improve performance of multi-physics simulations on massively parallel architectures, which is currently limited by problems of scale and overhead in data distribution and resource allocation. The effort will explore the various tradeoffs between overhead and parallelism, and will enable improved strategies in order to enable more efficient and more scalable computation for astrophysical and other problems.The project is expected to have a broad applicability of the project?s computational techniques beyond the direct problem of stellar mergers. A number of related problems in stellar astrophysics also require integrating the treatment of fluid dynamics, dynamic gravity, thermal and radiative transport, and nuclear energy generation. The group anticipates that the largest direct impact will come in the areas of supernova explosion modeling, the mergers of stars of various types, and stellar evolution when tidal effects and rotation are important.