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

在存在磁波动和湍流的情况下，首席研究员将重新审查日冕和行星际磁场的“相干通量管”范式的基础和局限性。他的研究小组将从场线随机游走（FLRW）效应以及磁通管弯曲和“切碎”引起标准磁通管图像扰动的模拟场开始，并最终导致其崩溃。然后，PI将通过几种引起通量管不规则性的湍流波动模型进行研究，并研究标准通量管模型如何失效。这项工作将影响我们对太阳高能粒子（sep）传播的理解。它还将对用于研究日冕结构、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）结构的标准光滑磁通管假设的准确性和局限性提供有价值的见解。PI的团队将研究场线输运的扩散随机游走极限以及与磁波动拓扑复杂性相关的完全随机化延迟。后一种效应被认为是对sep的“dropouts”或“channeling”的一种解释，PI将进一步评估这一概念。PI将研究在磁流体动力学（MHD）湍流的动力学模拟中，由宽带波动引起的从封闭到开放场线拓扑的统计转变，以及磁通管和拓扑结构的形成。他的团队将把已确定的相干通量管特性与太阳风数据进行比较。将采用定量估计和充分分析的理论，并在可行时采用数值验证。PI断言，这一努力将使人们更好地认识到用于从天体物理学到空间天气预报等广泛研究领域的光滑通量管模型的局限性。一名博士生将是这项工作的关键参与者，这项工作将涉及与泰国和阿根廷的科学家建立伙伴关系。

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.