ANSWERS: Understanding and Forecasting Solar Energetic Particles in the Inner Solar System and Earth's Magnetosphere

太阳上的爆发事件，如太阳耀斑和日冕物质抛射(CME)，可以极大地激发电子、质子和重离子的能量。当这些“太阳高能粒子”(SEP)与地球相互作用时，它们就是一种潜在的太空天气危险。它们可能会对航空电子设备、卫星和宇航员产生不利影响。预测SEP事件是一个挑战，因为它们是不可预测的，而且粒子可以在太阳事件发生后几分钟到几个小时内到达地球。为了减轻SEPS对我们依赖技术的社会的有害影响，我们需要彻底了解这些高能粒子是如何在太阳系中运输和加速的，特别是在近地空间。由于问题的性质和规模，这种理解需要多个学科的研究人员合作努力，包括太阳物理、空间物理和地球空间科学、等离子体物理和粒子物理。在这个项目中，来自阿拉巴马大学亨茨维尔分校(UAH)、密歇根大学(UM)、威斯康星大学河瀑布分校和国家太阳天文台的一个多学科团队将开发一个全面的科学模型来理解和预测SEP。他们将创建一个由UAH和UM托管的基于网络的SEP预报工具，供空间气象界使用。大学生和博士后研究员将在该项目的各个方面发挥领导作用。因此，这一前沿研究工作的更广泛影响在于它有可能提高社会对空间气象灾害的复原力，同时促进我国在空间科学和空间气象方面的专门知识。该项目将开发一个全面的科学模型，以了解和预测日冕物质抛射如何影响内太阳系和地球磁层的高能粒子辐射环境，并将结果与地球表面的测量结果进行比较。两个广泛使用的模型，空间天气建模框架(SWMF)和改进的日光层粒子加速和传输模型(IPATH)将被耦合。SWMF和IPATH的现有差距将通过开发两个新模型来弥合：一个是机器学习辅助的日冕下部CME模型，另一个是从拉格朗日L1点向磁层输送的粒子跟踪模型。综合模型将提供模拟从CME发射到地面中子监测器探测到的信号的SEPS传播的能力，并考虑到对星系宇宙线的影响，例如福布什下降。模型验证将包括与中子监测数据进行比较，以了解第23和24太阳周期期间的一些地面增强和大型SEP事件。将通过网络界面向空间气象界开放使用综合SEP/GCR预报工具。每天将提供L1点和磁层内部SEP/GCR通量的预报，以及中子监测通量(如果适用)，每隔8小时提供一次。鉴于人们对日地系统科学的兴趣与日俱增，阿肯色州大学将开设一门关于磁层物理的研究生课程。本科生和研究生以及职业生涯早期的研究人员，包括一名博士后学者，将全面参与研究和外联工作。Answers项目将通过填补有关日地耦合系统的关键知识空白，促进国家的STEM专业知识和社会对空间天气灾害的适应能力。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Eruptive events on the Sun such as solar flares and coronal mass ejections (CMEs) can greatly energize electrons, protons and heavy ions. When these "solar energetic particles" (SEPs) interact with the Earth, they are a potential space weather hazard. They can have adverse impacts on avionics, satellites, and astronauts. Forecasting SEP events is a challenge because they are unpredictable and the particles can arrive at Earth within minutes to hours of the solar event. To mitigate the harmful effects due to SEPs on our technology-dependent society, we need a thorough understanding of how such energetic particles are transported and accelerated in the solar system, particularly in near-Earth space. Due to the nature and scale of the problem, such an understanding requires collaborative efforts from researchers in multiple disciplines, including solar physics, space physics and geospace sciences, plasma physics and particle physics. In this project, a multidisciplinary team from the University of Alabama in Huntsville (UAH), University of Michigan (UM), University of Wisconsin at River Falls, and the National Solar Observatory will develop a comprehensive scientific model to understand and forecast SEPs. They will create a web-based SEP forecasting tool hosted by UAH and UM for use by the space weather community. University students and a postdoctoral researcher will have leadership roles in all aspects of the project. The broader impacts of this cutting-edge research effort are thus in its potential to improve societal resilience to a space weather hazard while advancing our nation's expertise in space science and space weather. This project will develop a comprehensive scientific model to understand and predict how CMEs influence the energetic particle radiation environment in the inner solar system and Earth's magnetosphere, and compare the results with measurements at the Earth's surface. Two widely used models, the Space Weather Modeling Framework (SWMF) and the improved Particle Acceleration and Transport in the Heliosphere model (iPATH) will be coupled. Existing gaps in SWMF and iPATH will be bridged by developing two new models: a machine learning-assisted CME model for the lower solar corona, and a particle tracing model for transport from the Lagrange L1 point into the magnetosphere. The integrated model will provide the ability to simulate the propagation of SEPs from CME launch to signals detected by ground-based neutron monitors, and account for effects on galactic cosmic rays, e.g., the Forbush decrease. Model validation will include comparison with neutron monitor data for a number of ground level enhancements and large SEP events during solar cycles 23 and 24. An integrated SEP/GCR Forecasting Tool will be made openly accessible to the space weather community through a web interface. Daily forecast of the SEP/GCR flux at the L1 point and inside the magnetosphere, as well as neutron monitor flux (when applicable) will be provided at 8-hour intervals. Given the increased interest in Sun-Earth system science, a graduate level course on magnetospheric physics will be developed at UAH. Undergraduate and graduate students and early-career researchers including a postdoctoral scholar will be fully involved in the research and outreach efforts. ANSWERS projects will advance the nation’s STEM expertise and societal resilience to space weather hazards by filling key knowledge gaps regarding the coupled Sun-Earth system.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.