SHINE: Coronal and Interplanetary Magnetic Field: Structure, Topology, Flux Tubes, Transport, and Application to Energetic Particles

SHINE：日冕和行星际磁场：结构、拓扑、通量管、输运以及高能粒子的应用

• 批准号: 1156094
• 负责人: William Matthaeus
• 金额: $ 38.23万
• 依托单位: University of Delaware
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-03-01 至 2016-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1156094&HistoricalAwards=false
• 关键词: SHINE; Coronal; Interplanetary; Magnetic; Field

As the scientific motivation for this project, the principal investigator (PI) and his team note that the space physics community currently relies on solar magnetic field models that assume it is meaningful to represent flux tubes as coherent objects that extend over distances ranging from fractions of a solar radius to many Astronomical Units. In order to place this fundamental assumption on a firmer basis, the PI's team will examine the limitations of this "coherent flux tube" paradigm when magnetic fluctuations are present and they will study how to extend beyond this conceptual framework using several approaches. The team will apply magnetic field models and nonlinear transport theory to quantify Field Line Random Walk effects, as well as the flux tube meandering and "shredding" that causes the eventual breakdown of the standard flux tube scenario. The team will investigate these phenomena using "Reduced Magnetohydrodynamics" (Reduced MHD) physics models, an approach that is well tested in solar corona studies. The PI's team will also study the often neglected implications of isotropic field line and particle transport, where particle trapping becomes very important. The team will examine the relationship between field line transport and the intermittent character of real turbulent fields, and apply this knowledge to examine the well-known "dropouts" and "channeling" of solar energetic particles (SEPs) that have been observed. The team will investigate the time-dependent interaction of flux tubes by introducing the concept of "component interchange reconnection" and exploring its consequences for the topological structure of magnetic fields in the solar wind and in dynamical simulations of MHD turbulence. The broader impacts of this effort include improving our recognition of the limitations of existing flux tube models, and how these limitations apply to research areas ranging from astrophysics to space weather forecasting. In particular, this work will have an immediate impact on our understanding of the propagation of SEPs in a space weather context. The PI will also provide mentoring for several postdoctoral fellows and widely disseminate these research results at solar physics community workshops.

作为该项目的科学动机，首席研究员（PI）及其团队指出，空间物理界目前依赖太阳能磁场模型，这些模型假定将通量管作为相干物体具有有意义的距离，这些物体延伸了，从远距离的距离延伸，范围从单位半径的分数到许多天文学单位。为了更牢固地将这一基本假设放置，PI的团队将在存在磁性波动时检查这种“连贯的通量管”范式的局限性，他们将使用多种方法研究如何超越此概念框架。该团队将采用磁场模型和非线性传输理论来量化场线随机行走效果，以及磁通管曲折和“切碎”，这会导致标准通量管场景的最终崩溃。该团队将使用“减少磁水动力学”（减少MHD）物理模型研究这些现象，该方法在太阳能电晕研究中经过了很好的测试。 PI的团队还将研究各向同性场系和粒子传输的含义，在该粒子捕获变得非常重要。该团队将检查现场线运输与实际湍流场的间歇性特征之间的关系，并应用这些知识来检查已观察到的太阳能颗粒（SEP）的众所周知的“脱落”和“通道”。该团队将通过引入“组件交换重新连接”的概念并探索其对太阳风中磁场拓扑结构的后果以及在MHD湍流的动态模拟中探索其对磁场拓扑结构的后果，研究通量管的时间相互作用。这项工作的更广泛的影响包括提高我们对现有通量管模型的局限性的认识，以及这些局限性如何适用于从天体物理学到太空天气预测的研究领域。特别是，这项工作将立即影响我们对太空天气环境中SEP传播的理解。 PI还将为几个博士后研究员提供指导，并在太阳能物理社区研讨会上广泛传播这些研究结果。