Global Transport of Magnetic Energy in Active Regions on the Sun

太阳大气层中不稳定的磁结构是太阳喷发事件的根源，这些喷发事件可能会在近地空间环境和高层大气中造成严重扰动。我们的社会正变得越来越依赖技术资产，这些资产容易受到这些所谓的空间天气事件的影响。因此，预测此类事件的发生和详细性质对于将其损害降至最低至关重要。了解太阳大气中大尺度磁活动区的形成和动态发展是当前太阳物理学研究的热点问题。这个项目将执行一系列高度复杂和对计算要求很高的数值模拟，以阐明基本的物理过程和相互作用。这项研究首次描述了太阳内部和大气之间在整个物理条件范围内的耦合，以及大活动区特有的不同时空尺度。它将通过利用新开发的先进计算技术和访问超级计算机资源来做到这一点。这一活动区模式的进一步发展和测试是建立太阳事件预测能力的关键一步。这项研究中进行的数值实验将产生对其他正在进行的太阳磁活动建模工作有用的数据集，数值技术还有许多额外的应用，特别是在天体物理学领域。最后，这项工作成果将在开放源码许可下公开提供，允许其他有兴趣使用三维笛卡尔或球面辐射磁流体模型描述物理系统的研究人员或教育工作者使用它。主要的科学目标是更好地理解活动区域出现和演化时太阳内部和大气之间的耦合，以及在各种物理条件下的磁能传输，以及对流区到日冕系统的不同空间和时间尺度。为解决这一问题，新开发的球面版本的辐射磁流体力学程序RADMHD将被用来对通过上对流进入日冕的活动区磁通量涌现进行数值模拟。这些模拟的独特之处在于，它们将首次产生自洽和自给自足的模型，描述球面几何结构中从上对流区到日冕的大规模活动区磁场的出现和演化。磁通量将从下方引入该区域，使用现有通过深部出现的磁通量计算的数据，并将研究整个区域的电磁能量传输，因为活动区磁场与对流湍流相互作用，并使其径向向外进入模式大气。将在三个不同的空间尺度上进行三组通量涌现的数值模拟：(1)单个活动区，(2)两个非常接近的活动区，(3)在全球磁环境中两个相距很远的活动区。

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.