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

SHINE：日冕和行星际磁场：结构、拓扑、通量管、高能粒子传输

• 批准号: 0752135
• 负责人: William Matthaeus
• 金额: $ 31.18万
• 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: 2008
• 资助国家: 美国
• 起止时间: 2008-03-01 至 2012-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0752135&HistoricalAwards=false
• 关键词: SHINE; Coronal; Interplanetary; Magnetic; Field

The Principal Investigator (PI) will re-examine the basis for, and the limitations of, the "coherent flux tube" paradigm for coronal and interplanetary magnetic fields, in situations where magnetic fluctuations and turbulence are present. His research team will start from modeled fields in which Field Line Random Walk (FLRW) effects, as well as flux tube meandering and "shredding," cause perturbations of the standard flux tube picture, and eventually its breakdown. The PI will then progress through several models of turbulent fluctuations which give rise to flux tube irregularity, and investigate how the standard flux tube model breaks down. This work will impact our understanding of the propagation of solar energetic particles (SEPs). It will also provide valuable insights into the accuracy and limitations of standard smooth flux tube assumptions used in studying coronal structure, plasma heating models, models of the interplanetary magnetic field, and interplanetary coronal mass ejection (ICME) structure.The PI's team will investigate the diffusive random walk limit of field line transport and the delay of full randomization associated with the topological complexity of magnetic fluctuations. The latter effect has been suggested as an explanation of "dropouts" or "channeling" of SEPs, and the PI will further evaluate this concept. The PI will examine the statistical transition from closed to open field line topology that is induced by addition of broadband fluctuations, as well as the formation of flux tubes and topological structure in dynamical simulations of magnetohydrodynamic (MHD) turbulence. His team will compare identified coherent flux tube properties with solar wind data. Quantitative estimates and fully analytical theories will be used, and numerical verification will be applied as feasible. The PI asserts that this effort will result in better recognition of the limitations of the smooth flux tube models that are used in a broad range of research fields, from astrophysics to space weather prediction. A PhD student will be a key participant in this work, which will involve partnerships with scientists in Thailand and Argentina.

首席研究员（PI）将重新审查的基础上，和局限性，日冕和行星际磁场的“相干通量管”范例，在磁波动和湍流的情况下。他的研究团队将从模型场开始，其中场线随机游走（FLRW）效应以及通量管蜿蜒和“粉碎”会导致标准通量管图像的扰动，并最终导致其崩溃。然后，PI将通过几个模型的湍流波动，导致通量管的不规则性，并调查如何标准通量管模型打破。这项工作将影响我们对太阳高能粒子（SEP）传播的理解。它还将提供有价值的见解，用于研究日冕结构，等离子体加热模型，行星际磁场模型和行星际日冕物质抛射（ICME）结构的标准光滑通量管假设的准确性和局限性。PI的团队将研究场线传输的扩散随机游走极限和与磁波动拓扑复杂性相关的完全随机化的延迟。后一种效应被认为是SEP“脱落”或“引导”的解释，PI将进一步评估这一概念。PI将研究由宽带波动引起的从封闭到开放场线拓扑的统计过渡，以及磁流体动力学（MHD）湍流动态模拟中通量管和拓扑结构的形成。他的研究小组将把确定的相干通量管特性与太阳风数据进行比较。将使用定量估计和完全分析的理论，并在可行时进行数值验证。PI声称，这一努力将使人们更好地认识到从天体物理学到空间天气预测等广泛研究领域中使用的光滑通量管模型的局限性。一名博士生将是这项工作的主要参与者，这项工作将涉及与泰国和阿根廷科学家的伙伴关系。