Collaborative Research: SHINE--Using Photospheric Imprints of Coronal Currents to Understand Coronal Magnetic Structure

合作研究：SHINE——利用日冕电流的光球印记来了解日冕磁结构

• 批准号: 2302698
• 负责人: Stuart Gilchrist
• 金额: $ 10.76万
• 依托单位: Planetary Science Institute
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-06-01 至 2026-05-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2302698&HistoricalAwards=false
• 关键词: Collaborative; Research; SHINE; Using; Photospheric

Solar flares and coronal mass ejections (CMEs) drive the strongest disturbances in the solar system. These events are powered by the sudden release of magnetic energy stored in electric currents flowing in the coronal magnetic field. Basic questions about these currents remain: How do coronal currents evolve to become unstable in the lead up to such events? And how do these currents evolve to release magnetic energy during flares and CMEs? This project addresses these questions through modeling and analysis of coronal extreme ultra violet (EUV) images. The broader impacts include mentoring of undergraduate students and collaboration between US and Australian institutes. Outreach will be conducted for the Great American October 2023 and April 2024 solar eclipses. This project will employ Gauss’s separation method — which has a long heritage in terrestrial and planetary magnetism — to photospheric vector magnetograms (2D maps of the 3-component magnetic field) of solar active regions (ARs). The core idea of Gauss’s method is that the photospheric field can be unambiguously partitioned into three distinct parts, each with its own source: currents below the photosphere, currents above it, and currents passing through it. We refer to the part of the photospheric field due to coronal currents as the ”photospheric imprint” of these currents. Photospheric imprints, by themselves, cannot fully reveal the nature of coronal currents. Nonlinear, force-free field (NLFFF) extrapolations have previously been used to study coronal currents, but fields on these models’ bottom boundaries typically exhibit substantial inconsistencies with magnetogram fields. While both methods have limitations, combining them can substantially improve our under- standing of coronal currents. Accordingly, the project will exploit both approaches in case studies of flare- and CME-prone ARs, to investigate the structure and development of coronal currents. The team will analyze evolution in photospheric imprints and NLFFF models before and after flares/CMEs, and in quiet epochs to establish baseline rates of change. Coronal EUV images will also be studied for context.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.

太阳耀斑和冠状质量弹出（CME）驱动太阳系中的强灾害。这些事件是由于在冠状磁场中流动的电流中储存的磁能的突然释放提供了动力。有关这些电流的基本问题仍然存在：冠状电流如何发展成为此类事件的不稳定？这些电流如何演变为在耀斑和CME期间释放磁能？该项目通过建模和分析冠状动脉极端紫罗兰（EUV）图像来解决这些问题。更广泛的影响包括对本科生的心理以及我们与澳大利亚学院之间的合作。将于2023年10月和2024年4月的太阳能日食进行外展活动。该项目将采用高斯的分离方法（在地面和行星磁性中具有很长的遗产）来对太阳能活动区域（ARS）的光弹磁力图（3组分磁场的2D地图）（ARS）。高斯方法的核心思想是，可以将光球字段明确划分为三个不同的部分，每个部分都有其自身的来源：电流下方的电流，水流上方的电流以及通过它的电流。由于冠状电流，我们将Photophere字段的一部分称为这些电流的“光电烙印”。以前已经使用了非线性，无力场（NLFFF）外推的光球烙印来研究冠状电流，但是这些模型的底部边界上的字段通常会与磁通图接触到实质性的不一致。尽管两种方法都有局限性，但将它们结合起来可以大大改善我们对冠状电流的不足。彼此之间，该项目将在耀斑和CME易发的ARS的案例研究中利用这两种方法，以研究冠状电流的结构和发展。该团队将在Flares/CMES之前和之后分析Photopheric烙印和NLFFF模型的演变，并在安静的时期内建立变化的基线速率。该奖项反映了NSF的法定使命，并通过使用基金会的知识分子优点和更广泛的影响评论标准来反映了冠状图像。