Why Do Active Regions Erupt? Modeling of Active Region from Pre-Eruptive to Eruptive Processes

太阳爆发对近地环境有重大影响，这是由于轰击地球的高能粒子通量增加以及嵌入的磁性结构影响地球磁层。 这对我们在太空和地面的技术资产造成严重后果，包括中断远程通信，危及宇航员的安全，破坏卫星和电网。 因此，对太阳爆发和日冕相关磁场演变的重点调查有可能揭示太阳空间天气驱动因素的潜在物理机制。 这个为期三年的项目旨在通过数据驱动的三维数值模拟研究太阳爆发的物理起源。 该项目也有一个强大的教育组成部分，因为它提供了博士学位的部分支持。他是亨茨维尔市亚拉巴马大学的一名学生和初级科学家。 因此，该项目的研究和EPO议程支持AGS部门在发现，学习，多样性和跨学科研究方面的战略目标。这个为期3年的项目旨在回答有关太阳爆发的物理起源和演变的一些基本问题，这将扩大太阳耀斑和日冕物质抛射（CME）期间能量释放的现有知识的前沿太阳和太阳日冕的相关重新配置。 基本研究目标是：了解基本的活动区喷发物理学;提供一个实用工具，作为开发基于物理学的数据驱动空间气象预测代码的初始模型。 研究计划是利用项目小组开发的MHD-DARE模型，以及太阳动力学观测台（SDO）上HMI和AIA仪器的观测数据，解决以下科学问题：（i）太阳爆发前磁场结构的基本特征是什么？(ii)光球表面的运动，包括切变、会聚和通量抵消，是如何使最初出现的场变成如此不稳定的结构的？(iii)磁通绳和磁场重联在引发太阳爆发中扮演什么样的具体角色？(iv)我们能否从磁场的拓扑结构和演化来理解各种耀斑/喷发过程的复杂性？以及，（v）太阳爆发如何在光球场上留下印记？ AR开发的这些方面将与太阳爆发之前和期间日冕场的演变有关，为此，项目团队将使用MHD-DARE模型进行由随时间变化的矢量磁图驱动的数值模拟。 然后，将分析模拟结果，以产生磁拓扑结构，电流，等离子体流和洛伦兹力的演变，以确定太阳爆发的主要触发机制，并将它们与相关的太阳观测进行比较。 此外，项目小组计划进一步改进目前的模型，包括一个现实的能量方程和直接从光球层进入日冕的等离子体配置。

Solar eruptions have significant impact on the near-Earth environment due to the enhanced flux of energetic particles bombarding the Earth and the embedded magnetic structures impacting the Earth's magnetosphere. This has serious consequences for our technological assets both in space and on the ground, including interruption of tele-communication, compromising the safety of astronauts, and damaging satellites and electric power grids. Therefore, focused investigations of solar eruptions and the associated magnetic field evolution of the solar corona have the potential to reveal the underlying physical mechanism(s) of the drivers of space weather at the Sun. This 3-year project is aimed at investigating the physical origins of solar eruptions at the Sun by means of data-driven, three-dimensional (3-D) numerical simulations. The project also has a strong educational component as it provides partial support for a Ph.D. student and a junior scientist at the University of Alabama in Huntsville. Thus, the research and EPO agenda of this project supports the Strategic Goals of the AGS Division in discovery, learning, diversity, and interdisciplinary research.This 3-year project is aimed at answering some of the fundamental questions concerning the physical origin and evolution of solar eruptions, which will expand the frontier of existing knowledge on the energy release during solar flares and Coronal Mass Ejections (CMEs) on the Sun and the associated reconfiguration of the solar corona. The underlying research objectives are: (i) understanding the fundamental active region (AR) eruptive physics; and, (ii) providing a practical tool as an initiation model for the development of a physics-based data-driven space weather prediction code. The research plan is to use the MHD-DARE model developed by the project team, together with observational data from the HMI and AIA instruments onboard the Solar Dynamics Observatory (SDO), to address the following science questions: (i) what are the basic characteristics of magnetic field configuration before a solar eruption?; (ii) how do photospheric surface motions, including shear, convergence and flux cancellation bring the initial emerged fields to such an unstable configuration?; (iii) what are the specific roles played by magnetic flux rope and magnetic reconnection in triggering solar eruptions?; (iv) can we understand the complexity of various flare/eruption process from topology and evolution of the magnetic field?; and, (v) how do solar eruptions leave imprints on the photospheric fields? These aspects of the AR development will be connected to the evolution of the coronal field long before and during a solar eruption, for which the project team will use the MHD-DARE model to carry out numerical simulations driven by the time-dependent vector magnetograms. Then, the simulation results will be analyzed to yield the evolution of the magnetic topology, electric currents, plasma flows, and Lorentz force to determine the primary triggering mechanisms of the solar eruption, and they will be compared with relevant solar observations. In addition, the project team plans to further improve the current model by including a realistic energy equation and a plasma configuration directly from the photosphere into the solar corona.