Magnetospheric Ducts and Their Role and Importance in Whistler Mode Wave Propagation and Wave-particle Interactions in the Inner Magnetosphere

在地球空间环境下，大尺度（10-100 km）场向磁层管道对磁层和电离层的动力学和能量输运具有重要意义。这些区域具有不规则的密度增强和消耗，从而影响波粒相互作用的性质。该项目研究了这一过程，并可能导致天基技术的改进，包括GPS和卫星通信，以及空间天气的预测模型。该项目支持一名研究生和一名早期职业助理教授。尽管它们在内磁层的物理学中很重要，但由于以前没有开发出适当的实验方法，因此对磁性管道的测量相对较少。IMAGE卫星的惠斯勒模式（WM）和Z模式（ZM）探测为测量场向电子密度和磁层导管提供了新一代方法。利用这些新方法，将对磁层导管进行研究，并对导管在磁层内部过程中的作用和重要性有新的认识。该项目的目标是：(1)获得新的管道宽度、密度增强、出现模式和形态作为地磁和太阳活动的函数的测量结果；(2)对导致管道形成、维持和腐烂的物理过程有新的认识；(3)对管道在磁层内部过程中的作用有了新的认识。将采用一种涉及数据分析和光线追踪模拟的方法来实现上述目标。来自RPI/IMAGE的WM和ZM无线电探测和无源测量将是本研究中使用的主要数据来源。将利用其他地面和空间仪器（例如地面甚高频接收器；卫星波和粒子探测器）提供的互补波和粒子数据，扩大和加强从WM和ZM无线电探测获得的结果。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

In the geospace environment, large-scale (10-100 km) field-aligned magnetospheric ducts are important to the dynamics and energy transport of the magnetosphere and ionosphere. These regions have irregular density enhancements and depletions that affect the nature of wave-particle interactions. The project studies this process and could lead to improvements of space-based technology, including GPS and satellite communications, and predictive models of space weather. The project supports a graduate student and early career assistant professor.Despite their importance in the physics of the inner magnetosphere, relatively few measurements of magnetic ducts are available because appropriate experimental methods have previously not been developed. Whistler mode (WM) and Z- mode (ZM) sounding from the IMAGE satellite provides a new generation of methods to measure field-aligned electron density and magnetospheric ducts. Using these new methods, the research will investigate magnetospheric ducts and develop a new understanding of the role and importance of ducts in inner magnetospheric processes. The objectives of the project are: (1) to obtain new measurements of duct widths, density enhancements, and occurrence patterns and morphology as a function of geomagnetic and solar activity; (2) to gain new understanding of physical processes that lead to the formation, sustenance, and decay of ducts; and (3) to gain a new understanding of the role of ducts in inner magnetospheric processes. An approach involving data analysis and ray tracing simulations will be used to achieve the objectives described above. The WM and ZM radio sounding and passive measurements from RPI/IMAGE will be the principal source of data used in this research. Results obtained from WM and ZM radio sounding will be augmented and enhanced using complementary wave and particle data available from other ground and space-borne instruments (e.g. ground VLF receivers; satellite wave and particle detectors).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.