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

太阳活动是地球严重空间天气的主要驱动力。潜在的最危险的事件是爆发性X级耀斑/日冕物质抛射（CME），它们可能导致重大的地磁风暴和危险的太阳高能粒子。1859年的“卡林顿”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。类似卡林顿事件的极端太阳爆发发生在太空时代，但幸运的是，主要不是地球。对其他恒星的观测，以及对宇宙起源放射性核素的测量，暗示着更猛烈的爆发是可能的。所有这些事件的驱动力是储存在强大的太阳活动区磁场中的磁能，然后爆炸性地释放出来。该项目将（1）从根本上提高我们对产生极端太阳爆发的区域的理解，（2）确定预示即将发生的极端事件及其可能的规模的条件。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一名博士生的论文研究，从而有助于NSF的教育目标。这项研究的重点是五个科学问题：是什么决定了多少能量可以存储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，可能发生的最大的喷发是什么？多次喷发在最大限度地发挥地球效应结构方面发挥了什么作用？卡林顿式或更大规模喷发的统计可能性是多少？这些问题将使用非线性无力场模型，磁流体动力学模拟，分析磁通绳模型，和部分开放领域的理论来研究在太空时代已经观察到的一些最大和最复杂的AR的爆发。通过将相关的日冕物质抛射传播到地球轨道，将推断出最极端事件可能在地球产生的空间气象相关参数的最大值。40年来太阳活动区的磁力数据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暴的发生概率）将被用来计算在给定的十年内卡林顿式或更严重的太阳爆发的概率。该奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

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.