Collaborative Research: PREEVENTS Track 2: Quantifying the Risk of Extreme Solar Eruptions (QUEST)

太阳活动是地球上恶劣空间天气的主要驱动因素。潜在的最危险的事件是爆发的x级耀斑/日冕物质抛射（CME），它可以引起主要的地磁风暴和危险的太阳高能粒子。1859年的“卡灵顿”事件，如果发生在今天，将对我们的技术基础设施造成重大破坏。类似卡灵顿事件的极端太阳爆发在太空时代也发生过，但幸运的是，主要不是针对地球的。对其他恒星的观测，以及对宇宙形成放射性核素的测量对我们过去的一瞥，表明可能会有更猛烈的爆发。所有这些事件的驱动因素是储存在强大的太阳活跃区磁场中的磁能，然后爆炸释放。该项目将(1)从根本上增强我们对产生极端太阳爆发的地区的了解，(2)确定预示即将发生的极端事件的条件及其可能的规模。为了让公众能够接触到科学，该团队将利用并加强社区协调建模中心和纽约美国自然历史博物馆之间的持续合作关系，为高影响力的公共展览提供引人注目的可视化效果。该项目将支持夏威夷大学博士生的论文研究，从而为NSF的教育目标做出贡献。这项研究集中在五个科学问题上：是什么决定了可以储存多少能量来驱动主要的太阳爆发？是什么决定了在这些喷发中释放的储存能量的比例？根据已知的太阳活动区域，最大的喷发可能是什么？多次喷发在使地质有效构造最大化方面起什么作用？发生卡灵顿式或更大规模喷发的统计可能性有多大？这些问题将使用非线性无力场模型、磁流体动力学模拟、解析通量绳模型和部分开放场理论来研究在太空时代观测到的一些最大和最复杂的ARs的喷发。通过将相关的日冕物质抛射传播到地球轨道，可以推断出地球上最极端事件可能产生的空间天气相关参数的最大值。来自太阳活动区域的磁数据跨越40年，将用于确定已知区域最大喷发的规模。最后，统计技术（以前用于估计极端地磁风暴发生的概率）将被用于计算在给定的十年中类似卡灵顿或更严重的太阳爆发的概率。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。

Solar activity is the primary driver of severe space weather at Earth. The potentially most dangerous events are eruptive X-class flares/Coronal Mass Ejections (CME) that can cause major geomagnetic storms and hazardous solar energetic particles. The 1859 "Carrington" event, if it were to happen in the present day, would cause significant damage to our technological infrastructure. Extreme solar eruptions of similar magnitude to the Carrington event have occurred in the space age, but fortunately were not primarily Earth directed. Observations of other stars, and glimpses into our past using measurements of cosmogenic radioactive nuclides, suggest that even more violent eruptions may be possible. The driver for all of these events is magnetic energy that is stored in powerful solar active region magnetic fields and then explosively released. This project will (1) fundamentally enhance our understanding of the regions that produce extreme solar eruptions, and (2) identify the conditions that foreshadow imminent extreme events and their possible magnitude. To make the science accessible to the general public, the team will leverage and enhance an ongoing partnership between the Community Coordinated Modeling Center and the American Natural History Museum of New York to provide compelling visualizations for high-impact public shows. This project will support the dissertation research of a PhD student at the University of Hawaii and thus contribute to the educational goals of NSF. This research focuses on five science questions: What determines how much energy can be stored to drive major solar eruptions? What determines the fraction of stored energy that is released in these eruptions? What is the largest possible eruption, based on known solar active regions? What roles do multiple eruptions play in maximizing geoeffective structures? What is the statistical likelihood of Carrington-like or greater size eruptions? These questions will be addressed using nonlinear force-free field models, magnetohydrodynamic simulations, analytic flux-rope models, and the theory of partially open fields to investigate eruptions for some of the largest and most complex ARs that have been observed during the space age. By propagating the associated CMEs to Earth's orbit, the maximum values will be inferred for space-weather relevant parameters that the most extreme events can produce at Earth. Magnetic data from solar active regions spanning four decades will be used to bound the size of the largest eruption for known regions. Finally, statistical techniques (previously used to estimate the occurrence-probability of extreme geomagnetic storms) will be employed to calculate the probability of a Carrington-like or worse solar eruption in a given decade.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.