Collaborative Research: Dynamic and Non-Force-Free Properties of Solar Active Regions and Subsequent Initiation of Flares

合作研究：太阳活动区域的动态和非无力特性以及随后耀斑的引发

• 批准号: 1954503
• 负责人: Qiang Hu
• 金额: $ 29.84万
• 依托单位: University of Alabama in Huntsville
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-04-01 至 2025-03-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1954503&HistoricalAwards=false
• 关键词: Collaborative; Research; Dynamic; Non; Force

Solar flares and coronal mass ejections (CMEs) correspond to a sudden, major reconfiguration of the coronal magnetic field. It has been well known that the topology and evolution of Sun's magnetic fields are determining factors in providing energy storage and initiation for solar eruptions. Although magnetic instabilities, such as torus and kink, are known to be related to onset of solar flares, it is still unclear how flare initiation is related to non-force-freeness and certain evolving structures of photospheric magnetic fields. These include small-scale magnetic reconnections, which are also signified by pre-flare brightenings. The use of state-of-the-art observations from the 1.6-m Goode Solar Telescope (GST) at the Big Bear Solar Observatory (BBSO), plus advanced magnetohydrodynamical (MHD) modeling tools and analysis techniques for the extrapolation of coronal magnetic field of the Sun matured significantly in recent years. The main purpose of this 3-year collaborative project is to expand the frontiers of existing knowledge on the magnetic energy release process occurring during solar flares. The research outcome of this project is expected to contribute to the scientific preparation for the future high-resolution solar flare studies, as well as the development of data analysis tools for the DKIST. The research project addresses some key science questions related to solar flares, namely: the non-force-free properties of solar atmosphere prior to eruptions, and the role of small-scale magnetic reconnections in the initiation of solar flares. Studying flare-associated magnetic field evolution promises to reveal the underlying physical mechanism of solar eruptions, which are the physical drivers of space weather at the Sun. Furthermore, this collaborative project has a strong educational and student training component. It will support two post-doctoral researchers: one at the NJIT and the other at the UAH, and a PhD student at the UAH. The NJIT will play a key role in training graduate students and young researchers to be the future users of the DKIST. The data analysis and imaging processing tools can be used by many other areas of science and engineering. Both the NJIT and UAH have a very diverse student population. The project will advance the education of underrepresented students in both institutions.The team will conduct a comprehensive study of solar flares in order to achieve a fundamental physical understanding of the aforementioned flare-related magnetic field evolution. The study will combine vector magnetograms from HMI, the spectropolarimeter of Hinode, and the high-resolution, high-cadence vector magnetograms from the GST. The high-resolution observations are necessary as they can reveal the fine details of dynamic magnetic field structures around flaring sites. The non-force-free properties of Sun's Active Regions (ARs) near the photosphere become even more prominent under these high-resolution observations. Three complementary sets of existing vector magnetograph data will be analyzed by the project teams. The SDO/HMI provides full-disk vector magnetograms with a cadence of about 2 to 12 minutes, which enable the study of the large-scale magnetic field structure and evolution. The BBSO/GST achieves a high resolution in the order of 0.1" and a temporal cadence of 30 seconds, thus providing a unique data source for studying the flare core regions in great details. The Hinode/SP data are obtained at a low cadence, but they cover a rich archive of flares since 2006 and provide a quality check for more recent GST magnetograms. The project teams will carry out Non-Force-Free Field (NFFF) extrapolations based on combined HMI, Hinode, and GST data and compare them with the more mature Non-Linear Force-Free Field (NLFFF) modeling results. The NFFF extrapolation will reveal the Lorentz force distribution and evolution of flare productive ARs. Using extrapolated coronal fields as initial conditions from extrapolations, the teams will apply 3D data-constraint and data-driven MHD modeling to select events. Using observations, extrapolation, and MHD simulations, the project teams will determine the role of non-force-freeness and evolving magnetic fields in flare initiation and precursor brightening. As part of the modeling validation, observed flare ribbon motion and the post-flare magnetic restructuring will be compared with the MHD modeling results. The research and EPO agenda of this project supports the Strategic Goals of the AGS Division in discovery, learning, diversity, and interdisciplinary research.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.

太阳耀斑和日冕物质抛射（CME）对应于日冕磁场的突然、重大的重新配置。 众所周知，太阳磁场的拓扑结构和演化是太阳能量储存和爆发的决定性因素。 虽然磁不稳定性，如环面和扭结，已知与太阳耀斑的爆发有关，但仍然不清楚耀斑的爆发与光球磁场的非力自由和某些演变结构的关系。 这些包括小规模的磁场重联，这也是由耀斑前的增亮所表示的。 近年来，利用大熊太阳观测站1.6米古德太阳望远镜的最新观测数据，加上先进的磁流体动力学建模工具和分析技术，对太阳日冕磁场进行外推的技术已经相当成熟。 这个为期3年的合作项目的主要目的是扩大现有知识的前沿，在太阳耀斑期间发生的磁能释放过程。 该项目的研究成果预计将有助于为未来的高分辨率太阳耀斑研究做好科学准备，并为DKIST开发数据分析工具。 该研究项目涉及与太阳耀斑有关的一些关键科学问题，即：爆发前太阳大气层的非无力性质，以及小规模磁重联在引发太阳耀斑中的作用。 研究耀斑相关的磁场演化有望揭示太阳爆发的潜在物理机制，这是太阳空间天气的物理驱动力。 此外，这一合作项目具有很强的教育和学生培训组成部分。 它将支持两名博士后研究人员：一名在NJIT，另一名在UAH，以及一名在UAH的博士生。 NJIT将在培养研究生和年轻研究人员成为DKIST的未来用户方面发挥关键作用。 数据分析和成像处理工具可用于许多其他科学和工程领域。 NJIT和UAH都有非常多样化的学生群体。 该项目将促进这两个机构中代表性不足的学生的教育，该小组将对太阳耀斑进行全面研究，以便对上述与耀斑有关的磁场演变有一个基本的物理认识。 这项研究将把来自HMI的联合收割机矢量磁图、Hinode的分光偏振仪和来自GST的高分辨率、高节奏矢量磁图结合起来。 高分辨率观测是必要的，因为它们可以揭示耀斑现场周围动态磁场结构的细节。 在这些高分辨率观测下，光球附近太阳活动区（AR）的非无力特性变得更加突出。 项目小组将分析三套互补的现有矢量磁象仪数据。 SDO/HMI提供了约2至12分钟节奏的全磁盘矢量磁图，这使得能够研究大尺度磁场结构和演化。 BBSO/GST达到了0.1”量级的高分辨率和30秒的时间节奏，从而为更详细地研究耀斑核心区域提供了独特的数据源。 日出/SP数据是在低节奏下获得的，但它们涵盖了自2006年以来丰富的耀斑档案，并为最近的GST磁图提供了质量检查。 项目团队将根据HMI、Hinode和GST数据进行非无力场（NFFF）外推，并将其与更成熟的非线性无力场（NLFFF）建模结果进行比较。 NFFF外推将揭示洛伦兹力的分布和耀斑产生AR的演化。 使用外推的日冕场作为外推的初始条件，团队将应用3D数据约束和数据驱动的MHD建模来选择事件。 利用观测、外推和MHD模拟，项目小组将确定非力自由和不断变化的磁场在耀斑起始和前兆增亮中的作用。 作为模型验证的一部分，观测到的耀斑带运动和耀斑后的磁重组将与MHD模型结果进行比较。 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。该奖项反映了NSF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。

项目成果

Comparison of the Hall Magnetohydrodynamics and Magnetohydrodynamics Evolution of a Flaring Solar Active Region

• DOI: 10.3847/1538-4357/ac3bce
• 发表时间: 2021-12
• 期刊: The Astrophysical Journal
• 作者: K. Bora;R. Bhattacharyya;A. Prasad;B. Joshi;Q. Hu

Quantitative Characterization of Magnetic Flux Rope Properties for Two Solar Eruption Events

• DOI: 10.3847/1538-4357/ac78df
• 发表时间: 2022-01
• 期刊: The Astrophysical Journal
• 作者: W. He;Q. Hu;C. Jiang;J. Qiu;A. Prasad

Magnetohydrodynamic Simulation of Magnetic Null-point Reconnections and Coronal Dimmings during the X2.1 Flare in NOAA AR 11283

• DOI: 10.3847/1538-4357/abb8d2
• 发表时间: 2020-09
• 期刊: The Astrophysical Journal
• 作者: A. Prasad;K. Dissauer;Q. Hu;R. Bhattacharyya;A. Veronig;Sanjay Kumar;B. Joshi

Coronal Magnetic Field Extrapolation and Topological Analysis of Fine-scale Structures during Solar Flare Precursors

• DOI: 10.3847/1538-4357/ad0236
• 发表时间: 2023-06
• 期刊: The Astrophysical Journal
• 作者: W. He;J. Jing;Haimin Wang;S. Nayak;A. Prasad

Effects of Cowling Resistivity in the Weakly Ionized Chromosphere

弱电离色球层罩电阻率的影响

• DOI: 10.3847/2041-8213/aba69a
• 发表时间: 2020
• 期刊: The Astrophysical Journal
• 作者: Yalim, M. S.;Prasad, A.;Pogorelov, N. V.;Zank, G. P.;Hu, Q.
• 通讯作者: Hu, Q.