Pathways to Coronal Magnetic Energy Storage and Release

日冕磁能储存和释放的途径

• 批准号: 1630454
• 负责人: Graham Barnes
• 金额: $ 51.16万
• 依托单位: NorthWest Research Associates, Incorporated
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-08-01 至 2021-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1630454&HistoricalAwards=false
• 关键词: Pathways; Coronal; Magnetic; Energy; Storage

This project science focuses on a fundamental gap in our knowledge of solar energetic events and their potential impact on the heliospheric and interplanetary environment - how to evaluate their potential size in terms of energy release. This project is unique in that it uses as statistics based approach to analyze characteristics of solar active regions. Being able to measure the stored and available energy, and to predict the size of an upcoming event will improve forecasting capability for solar flares and related phenomena such as coronal mass ejections and energetic particle production and propagation. These are the phenomena with direct impacts on human-dependent infrastructure and national security, hence improvements in forecasting eventually benefits large sectors of society. This project supports a postdoctoral researcher and a member of an underrepresented group who will serve as a mentor and Co-PI. Summer inters from the REU program will also be involved.The objective of this project is to understand the different pathways to the release of stored coronal magnetic energy. When a large amount of free energy is stored, some active regions release it in a few large events, while others release the same amount of energy in many smaller events. Why this occurs is unknown. Two complementary approaches will be used to investigate this: 1) using photospheric proxies for the energy for a large sample of events, and 2) modeling of the coronal magnetic field for a small sample of events. In each case, the energy will be computed for subareas within each active region to estimate the fraction of the total free energy that can be released in a flare. This will be compared to the GOES soft X-ray flux of the events. Verification statistics computed from discriminant analysis will be used to determine whether photospheric proxies for sub-areas of an active region are better then global proxies at distinguishing regions which produce large events versus those which produce only small events. If the analysis indicates that the free energy computed for sub-areas are more closely associated with the energy released, this will indicate that the local configuration of the field is more important than the global configuration. The corona will be modeled using the Minimum Current Corona model and nonlinear force-free field extrapolations. For both models, a detailed comparison will be made of the possible energy release pathways to the flares that occurred, and the location of the flare emission to the currents associated with the stored energy. This will provide insight into the underlying processes governing the production of energetic events.

该项目的科学重点是我们对太阳高能事件及其对日光层和行星际环境的潜在影响的知识的根本差距-如何评估其能量释放的潜在规模。该项目的独特之处在于它使用基于统计的方法来分析太阳活动区的特征。能够测量储存的和可用的能量，并预测即将发生的事件的规模，将提高对太阳耀斑和日冕物质抛射及高能粒子产生和传播等相关现象的预测能力。这些现象对依赖人类的基础设施和国家安全产生直接影响，因此预测的改进最终会使社会的大部分部门受益。该项目支持一名博士后研究人员和一名代表性不足的小组成员，他们将担任导师和共同PI。REU计划的夏季实习也将参与其中。这个项目的目标是了解储存的日冕磁能释放的不同途径。当储存了大量的自由能时，一些活动区域在几个大事件中释放它，而另一些活动区域在许多较小的事件中释放相同数量的能量。发生这种情况的原因尚不清楚。两种互补的方法将被用来研究这一点：1）使用光球代理的能量为大样本的事件，和2）模拟日冕磁场的小样本的事件。在每种情况下，将计算每个活动区域内的子区域的能量，以估计耀斑中可以释放的总自由能的比例。这将与事件的GOES软X射线通量进行比较。从判别分析计算出的验证统计数据将用于确定活动区分区的光球代用指标是否优于全球代用指标，以区分产生大事件的区域和只产生小事件的区域。如果分析表明，为子区域计算的自由能与释放的能量更密切相关，则这将表明场的局部配置比全局配置更重要。将使用最小电流电晕模型和非线性无力场外推法对电晕进行建模。对于这两个模型，将进行详细的比较，可能的能量释放途径的耀斑发生，和位置的耀斑发射到电流与存储的能量。这将提供深入了解的基本过程，管理生产的高能事件。

项目成果

A New Parameter of the Photospheric Magnetic Field to Distinguish Eruptive-flare Producing Solar Active Regions

• DOI: 10.3847/1538-4357/ab822c
• 发表时间: 2020-04
• 期刊: The Astrophysical Journal
• 作者: P. Lin;K. Kusano;D. Shiota;S. Inoue;K. Leka;Y. Mizuno

The NWRA Classification Infrastructure: Description and Extension to the Discriminant Analysis Flare Forecasting System (DAFFS)

• DOI: 10.1051/swsc/2018004
• 发表时间: 2018-02
• 期刊: arXiv: Solar and Stellar Astrophysics
• 作者: K. Leka;G. Barnes;E. Wagner