Sporadic e (ES) layers are characterized by density enhancements in the e-region of the ionosphere that vary from several times to an order of magnitude higher than background plasma density.…

Embry-Riddle Aeronautical University, Inc. received a $3.52M grant award from a civilian federal agency effective April 1, 2019, with a completion date of December 31, 2026, to conduct research on sporadic E layer electrodynamics. Sporadic E layers are density enhancements in the E-region of the ionosphere with significant implications for radio communication systems and ionospheric science. The research builds upon the university's prior work demonstrating that equatorial sporadic E layers are produced not only by wind shears but also by undulations in the vertical electric field, creating a complex feedback mechanism involving the F region dynamo that affects layer position and evolution. The research will examine electron temperature enhancements around these layers and investigate heating mechanisms driven by parallel current densities in the range of 1 to 2 microamps per square meter.

This grant is a non-set-aside award supporting fundamental research in space weather and atmospheric physics at Embry-Riddle's Daytona Beach, Florida campus. The work directly advances understanding of ionospheric electrodynamics and the physical mechanisms governing sporadic E layer formation and behavior, contributing to the broader national interest in space science and radio communication reliability. Embry-Riddle's established expertise in aerospace research and its role as a research-active institution make it well-suited to execute this multi-year investigation into complex ionospheric phenomena.

Sporadic e (ES) layers are characterized by density enhancements in the e-region of the ionosphere that vary from several times to an order of magnitude higher than background plasma density. Understanding the dynamics and physics of ES layers is of critical importance due to what they reveal about the dynamics and electrodynamics of the ionosphere, and the affect these ionized layers have on various radio communication systems. Our recent work has shown that near the equator, ES layers are produced not just by wind shears but also by undulations in the vertical electric field higher up in the e region. The undulations seem to themselves be triggered by the very modulation of the ES layer by the night-time f region dynamo, thereby introducing a complex feedback mechanism that strongly affects the position and evolution of the layer . We also showed electron temperature data that confirmed multiple observations of electron temperatures around ES layers that can be enhanced by up to 1000 k. We made a case for the heating rate being produced by parallel current densities of the order of 1 to 2 microamps/m^2. These currents were caused directly by the f region dynamo itself in the density troughs, while in the density maxima regions they were triggered by a divergence in the currents perpendicular to the magnetic field resulting from the ES layer itself in the presence of the observed f region generated electric fields.