Observation and Modeling of Global Propagation of Pi2 Waves

地球周围的空间等离子体环境中的风暴会产生超低频率（ULF）无线电波。这些波通过磁层将能量传输到大气的低层。了解这些波对国家安全和商业利益很重要，因为它们会对我们的卫星和天基通信造成空间天气影响。此外，物理学研究生将接受与来自多个科学机构的研究人员合作的研究技术培训。该研究旨在定量了解与一种称为Pi2波的ULF波的全球传播相关的过程。这些波在磁层亚暴开始时在夜侧磁层被激发，并传播到日侧和地面。这些波在结构磁层和电离层内长距离传播时是如何保持能量的，目前还不清楚。他们将通过分析来自航天器和地面的数据以及结合实际磁层和电离层进行数值模拟来解决这个问题。他们将使用同时运行超过1.5年的辐射带风暴探测器和Arase航天器的数据，覆盖不同的磁地方时和磁纬度。在模拟中，我们将使用偶极子场线性MHD代码，该代码结合了现实的电离层边界条件，并能够产生地面波场。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。

Storms in the space plasma environment surrounding the Earth create ultra-low frequency (ULF) radio waves. These waves transport energy throughout the magnetosphere into lower levels of the atmosphere. Understanding these waves is important to national security and commercial interests, since they contribute to space weather effects to our satellites and space-based communications. Additionally, a physics graduate student will be trained in research techniques engaging with researchers from multiple scientific institutions. The investigation seeks a quantitative understanding of processes associated with global propagation of a type of ULF waves known as Pi2 waves. The waves are excited in the nightside magnetosphere at the beginning of magnetospheric substorms and propagate to the dayside and to the ground. How the waves maintain their energy as they propagate over long distances within the structured magnetosphere and through the ionosphere is not well understood. They will tackle this problem by analysis of data from spacecraft and ground and by conducting numerical simulation incorporating realistic magnetosphere and ionosphere. They will use data from the Radiation Belt Storm Probes and Arase spacecraft, which have been in concurrent operation for more than 1.5 years, to cover different magnetic local times and magnetic latitudes. In the simulation, we will use a dipole field linear MHD code that incorporates realistic ionospheric boundary conditions and is capable of producing ground-level wave fields.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.