CEDAR: Neutral wind drivers of variability in the prereversal enhancement

点击翻译按钮获取中文摘要

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.