CEDAR: Neutral wind drivers of variability in the prereversal enhancement

地球的电离层是指靠近地球(距地面约90-1000公里)的空间区域，在那里存在大量的等离子体(离子和电子)。能够预测这一空间区域的变化很重要，因为它会影响无线电传播、GPS、超视距雷达、卫星通信和轨道再入。地球电离层的一个壮观特征是所谓的“预逆转增强”(PRE)，它发生在日落时，导致整个电离层向上移动长达100公里。在这个项目中，来自NASA的电离层连接探测器(ICON)航天器的新数据将被用来了解是什么机制导致PRE从一天到第二天和从一个经度到另一个经度的变化。以前从理论上预测了不同的机制，但从来没有用数据进行过测试。这项研究的结果有助于更好地预测赤道扩散F，它对通信和导航系统具有有害影响。除了科学影响，该项目还将通过对本科生的指导，使教育和STEM工作人员培训受益。该项目包括对ICON和Jicamara射电天文台(JRO)的数据进行分析。科学问题是：什么机制控制着Pre的纵向和日常变化？科学目标是确定中性风观测的特征，这些特征与跨经度和逐日的PRE强度的变化有关。首先，将进行验证研究，以确保ICON等离子体漂移和预估与JRO测量结果一致。下一步，将确定和比较预强风和中性风的纵向模式，有无独立的发电机解算器的帮助。每天的变化将通过比较前一天和下一天的变化和风向的变化来研究。这项工作将阐明导致Pre的机制，因此将有利于未来旨在预测和模拟Pre变率和赤道扩散F变率的工作。该奖项反映了NSF的法定使命，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。

The Earth's ionosphere is the region of space near Earth (~90-1000 km above the surface) where a significant population of plasma (ions and electrons) exists. It is important to be able to predict changes in this region of space because it affects radio propagation, GPS, over-the-horizon radar, satellite communication, and orbital re-entry. One spectacular feature of Earth's ionosphere is the so-called "pre-reversal enhancement" (PRE), which occurs at sunset and causes the entire ionosphere to move upward by up to 100 km. In this project, new data from NASA's Ionospheric Connection Explorer (ICON) spacecraft will be used to understand which mechanisms cause the PRE to change from one day to the next and from one longitude to the next. Different mechanisms have been previously predicted theoretically, but they have never before been tested with data. The results of this research could facilitate better predictions of equatorial spread F, which has deleterious effects on communication and navigation systems. In addition to the scientific impact, this project will benefit education and STEM workforce training via mentoring of undergraduate students.This project comprises an analysis of data from ICON and the Jicamarca Radio Observatory (JRO). The science question is: What mechanisms control the longitudinal and day-to-day variability of the PRE? The science objective is to determine the features of neutral wind observations that are correlated with changes in the strength of the PRE across longitudes and from day to day. First, a validation study will be performed to ensure that ICON plasma drifts and PRE estimates are consistent with JRO measurements. Next, longitudinal patterns of PRE strength and neutral winds will be determined and compared, with and without the aid of a standalone electrodynamo solver. Day-to-day variability will be studied by comparing changes in the PRE from one day to the next with changes in the wind. This work will elucidate mechanisms that cause the PRE and will therefore benefit future work that is aimed at predicting and modeling PRE variability and equatorial spread F variability.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.