Collaborative Research: SHINE--Exploring Reconnection-Driven Solar Explosive Events in Different Regimes through Modeling and Observation

合作研究：SHINE——通过建模和观测探索不同状态下重新连接驱动的太阳爆炸事件

• 批准号: 2301337
• 负责人: Yi-Min Huang
• 金额: $ 59.98万
• 依托单位: Princeton University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-07-15 至 2026-06-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2301337&HistoricalAwards=false
• 关键词: Collaborative; Research; SHINE; Exploring; Reconnection

Magnetic reconnection is the mechanism driving explosions on the Sun ranging from nanoflares, ultraviolet bursts, to inter-planetary sized coronal mass ejections. At the core of reconnection is a current sheet where magnetic energy is converted to plasma kinetic energy. This project investigates how plasmoid instabilities lead to reconnection and solar explosions. Magnetic reconnection is a primary driver of space weather and an important fundamental physical process important to space physics, fusion science, and astrophysics. The work supports research of mid-career and early career scientists, including graduate student support. The team will develop lectures to undergraduate students from under-represented groups through NASA’s Heliophysics Summer School.Recent theoretical analyses and numerical simulations predict that reconnection current sheets can spontaneously become unstable to the plasmoid instability. The plasmoid instability fractures the reconnecting current sheet into secondary current sheets, plasmoids, and flux ropes, facilitating the onset of fast reconnection. Depending on the collisionality and global system size in relation to kinetic scales, plasmoid-mediated re- connection can result in a variety of dynamical behaviors. Appropriately capturing critical properties of the dynamical behaviors is crucial for modeling explosive events. This project will develop a deeper understanding of the onset and saturation of plasmoid-mediated fast reconnection in various regimes through a concerted interdisciplinary effort of numerical simulation and solar observation. This is accomplished by: (1) Performing numerical simulations of solar explosive events including large-scale coronal mass ejections in the solar corona and ultraviolet burst events in the lower solar atmosphere. These events cover a broad range of length scales, plasma densities, and temperatures, corresponding to reconnection in different parameter regimes. Simulation results will be compared with observations. (2) Investigating the onset and saturation of fast reconnection in different parameter regimes. To establish a basic understanding of how various models behave in different regimes, the team will conduct 2D and 3D simulations of reconnection in a well-controlled current sheet using resistive magnetohydrodyamic (MHD), Hall MHD, and multi-moment multi-fluid codes to test how microscopic physics descriptions affect the onset and saturation of fast reconnection at large, observable scales.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.

磁重联是驱动太阳爆炸的机制，从纳米耀斑、紫外线爆发到行星间大小的日冕物质抛射。重新连接的核心是电流片，磁能在电流片上转化为等离子体动能。这个项目调查了等离子体不稳定如何导致重联和太阳爆炸。磁重联是空间天气的主要驱动力，也是对空间物理、聚变科学和天体物理重要的重要基本物理过程。这项工作支持职业生涯中期和职业生涯早期科学家的研究，包括研究生支持。该团队将通过NASA的太阳物理暑期学校为来自未被充分代表的群体的本科生开展讲座。最近的理论分析和数值模拟预测，重新连接电流片可能会自发地变得不稳定，从而导致等离子体不稳定。等离子体不稳定使重新连接的电流片断裂成二次电流片、等离子体和磁通绳，促进了快速重新连接的开始。根据碰撞程度和全球系统大小与动力学尺度的关系，等离子体介导的重新连接可以导致各种动力学行为。适当地捕捉动力学行为的关键性质对于建立爆炸事件的模型至关重要。这个项目将通过数值模拟和太阳观测的协调跨学科努力，加深对等离子体介导的快速重联在不同区域的开始和饱和的理解。这是通过：(1)对太阳爆发事件进行数值模拟，包括日冕中的大规模日冕物质抛射和太阳低层大气中的紫外线爆发事件。这些事件涵盖了大范围的长度尺度、等离子体密度和温度，对应于不同参数区域中的重新连接。模拟结果将与观测值进行比较。(2)研究了不同参数条件下快速重联的启动和饱和情况。为了建立对不同模型在不同体制下行为的基本理解，该团队将使用阻性磁流体动力学(MHD)、霍尔MHD和多时刻多流体代码在受控良好的电流片中进行重新连接的2D和3D模拟，以测试微观物理描述如何影响大规模、可观察到的快速重新连接的开始和饱和。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。