Global Transport of Magnetic Energy in Active Regions on the Sun

太阳活跃区域的磁能全球传输

• 批准号: 1455492
• 负责人: William Abbett
• 金额: $ 43.08万
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-12-15 至 2018-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1455492&HistoricalAwards=false
• 关键词: Global; Transport; Magnetic; Energy; Active

Unstable magnetic structures in the atmosphere of the Sun are the root source of eruptive events at the Sun that can cause severe perturbations in the near-Earth space environment and upper atmosphere. Our society is becoming increasingly dependent on technological assets that are vulnerable to these, so-called, space weather events. Consequently, predicting the occurrence and detailed nature of such events is of critical importance to minimizing their damage. Understanding the creation and dynamic development of large-scale magnetically active regions in the solar atmosphere is currently a topic of intense research in solar physics. This project will perform a series of highly complex and computationally demanding numerical simulations to illuminate the basic physical processes and interactions at play. The investigation is the first to describe the coupling between the solar interior and atmosphere over the entire range of physical conditions and disparate spatial and temporal scales characteristic of large active regions. It will do so by utilizing newly developed advanced computational techniques and access to supercomputer resources. The further development and test of this active region model constitute a critical step towards establishing a predictive capability for solar events. The numerical experiments performed in this study will generate data sets that are useful to other ongoing efforts to model solar magnetic activity and the numerical techniques have many additional applications, particularly in the field of astrophysics. Finally, the work product will be made publicly available under an OpenSource license allowing it to be used by other researchers or educators with an interest in describing physical systems using a three-dimensional, Cartesian or spherical, radiative magneto-hydro-dynamic model.The principal scientific objective is to better understand both the coupling between the solar interior and atmosphere as active regions emerge and evolve, and the transport of magnetic energy over the range of physical conditions, and the disparate spatial and temporal scales of the convection zone-to-corona system. To address this objective, the newly developed spherical version of the radiative-magneto-hydro-dynamic code RADMHD will be used to perform numerical simulations of active region magnetic flux emergence through the upper convection into the corona. The simulations are unique in that they will, for the first time, produce self-consistent and self-contained models of the emergence and evolution of large-scale active region magnetic fields spanning the upper convection zone-to-corona in spherical geometry. Magnetic flux will be introduced into the domain from below, using data from existing calculations of magnetic flux emergence through the deep interior, and the transport of electromagnetic energy throughout the domain will be studied as active region magnetic fields interact with convective turbulence and make their way radially outward into the model atmosphere. Three sets of numerical simulations of flux emergence on three distinct spatial scales will be performed: (1) a single active region, (2) two active regions in close proximity, and (3) two widely separated active regions in a global magnetic environment.

太阳大气中不稳定的磁结构是太阳喷发事件的根源，它会对近地空间环境和高层大气造成严重的扰动。我们的社会正变得越来越依赖于易受这些所谓的太空天气事件影响的技术资产。因此，预测此类事件的发生和详细性质对于尽量减少其损失至关重要。了解太阳大气中大规模磁活动区域的产生和动态发展是目前太阳物理学研究的热点。该项目将执行一系列高度复杂和计算要求高的数值模拟，以阐明基本的物理过程和相互作用。该研究首次描述了整个物理条件范围内太阳内部和大气之间的耦合以及大活动区的不同时空尺度特征。它将利用新开发的先进计算技术和获得超级计算机资源来实现这一目标。进一步发展和验证这一活动区模型是建立太阳事件预测能力的关键一步。在这项研究中进行的数值实验将产生对其他正在进行的模拟太阳磁活动的努力有用的数据集，并且数值技术有许多额外的应用，特别是在天体物理学领域。最后，工作成果将在开源许可下公开提供，允许其他对使用三维、笛卡尔或球形、辐射磁流体动力学模型描述物理系统感兴趣的研究人员或教育工作者使用。主要的科学目标是更好地理解活动区出现和演变时太阳内部和大气之间的耦合，以及在物理条件范围内的磁能传输，以及对流区-日冕系统的不同时空尺度。为了实现这一目标，将使用新开发的辐射磁流体动力学代码RADMHD的球形版本对通过上层对流进入日冕的活动区域磁通量进行数值模拟。这些模拟的独特之处在于，它们将首次产生自一致的、自包含的模型，用于在球面几何中跨越上层对流区和日冕的大规模活动区域磁场的出现和演化。磁通量将从下面引入该区域，利用现有的通过深层内部产生的磁通量的计算数据，并且电磁能在整个区域的传输将被研究，因为活跃区域磁场与对流湍流相互作用并向外径向进入模型大气。本文将在三个不同的空间尺度上进行三组通量出现的数值模拟：(1)单个活跃区，(2)两个距离较近的活跃区，以及(3)全球磁场环境中两个距离较远的活跃区。