Collaborative Research: GEM--Impact of Solar Wind Dynamic Pressure Enhancement on the Cusp and Polar Cap Ion Source

从电离层流出的离子是地球空间环境的主要粒子源之一。它们在地球同步轨道内区域的动态对空间天气扰动起着至关重要的作用，其影响包括卫星拖曳、通信和导航系统中断以及损坏电网。这个项目的重点是了解太阳的驱动因素之一--太阳风对地球空间的压缩--如何产生这些流出的离子及其运输的物理过程。压缩通常是强烈的和脉冲的，但我们目前对由此产生的流出离子的观测和模拟都知之甚少。这个项目将建立这样的知识，这是航天界迫切需要的，以提高我们对冲动性空间天气事件的预测能力。这个项目通过提供平衡的任务来支持研究生的教育，以发展学生在模拟和数据分析方面的基本研究能力。这个项目的科学目标是了解太阳风压缩如何影响流出离子。两个主要目标和方法是：(1)调查星团卫星数据，以便更好地观测到压缩引起的尖端和叶部离子通量的时间变化。(2)进行三维全球混合模拟，评估压缩引起的流出离子背后的物理过程。混合模拟是目前考虑这些流出离子的动力学过程的最合适的工具。模拟的目的是将其与观测结果进行比较，以建立坚实的物理理解。它还将改进我们目前的流出离子模型规范，最终可以纳入空间天气模型，以实现对太阳风压缩影响的更好预测。这一奖项反映了美国国家科学基金会的法定任务，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Outflow ions from the ionosphere are one of the major particle sources for the Earth's space environment. Their dynamics in the region inside the geosynchronous orbits play a crucial role in space weather disturbances, whose effects include satellite drag, disruption in communication and navigation systems, and damaging electric power grids. This project is focused on understanding the physical processes of how one of the drivers from the Sun, solar wind compression of the geospace, generates these outflow ions and their transport. The compression can often be strong and impulsive, but we currently have little knowledge in both observations and simulations on the resulting outflow ions. This project will establish such knowledge, which is urgently needed in the space community to improve our forecast ability for impulsive space weather events. This project supports the education of a graduate student by providing balanced tasks for developing the student's essential research ability in both simulations and data analysis.The science goal of this project is to understand how solar wind compression impacts outflow ions. The two main objectives and methods are (1) Investigating Cluster satellite data to establish a better observational understanding of temporal variations of the ion fluxes in the cusp and lobes resulting from the compression. (2) Conduct 3D global hybrid simulations to evaluate the physical processes behind the outflow ions caused by the compression. The hybrid simulation is currently the most appropriate tool to take into account the kinetic processes of these outflow ions. The simulations are designed to be compared with the observation results to establish a solid physical understanding. It will also improve our current model specification of the outflow ions that can eventually be incorporated into space weather modeling to achieve a better forecast of the impact of solar wind compression.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.