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.

在存在磁波动和湍流的情况下，主要研究者（PI）将重新检查冠状和行星际磁场的“相干通量管”范式的基础和局限性。他的研究团队将从建模的田地开始，其中野外线随机步行（FLRW）的效果以及通量管弯曲和“切碎”，这是标准通量管图片的扰动，最终是其崩溃的。然后，PI将通过几种湍流波动模型进行，这会导致通量管的不规则性，并研究标准通量管模型如何分解。这项工作将影响我们对太阳能颗粒（SEP）传播的理解。它还将提供有价值的见解，以了解用于研究冠状结构，血浆加热模型，星际磁场模型以及行星际冠状质量弹射（ICME）结构的标准平滑通量管假设的准确性和局限性。PI的团队将研究与磁场随机分析的差异随机步行限制与完整综合性的延迟性综合性相关性的范围随机步行限制。后一种效应被提出是对SEP的“辍学”或“渠道”的解释，PI将进一步评估这一概念。 PI将检查从闭合到开放田线拓扑的统计转变，该拓扑是通过添加宽带波动引起的，以及在磁性水力动力学（MHD）湍流动力学模拟中通量管和拓扑结构的形成。他的团队将将确定的连贯的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理论，并将数值验证应用于可行。 PI断言，这项工作将使从天体物理学到太空天气预测的广泛研究领域中使用的平滑通量管模型的局限性。博士生将成为这项工作的关键参与者，该研究将涉及与泰国和阿根廷科学家的合作伙伴关系。