Date of Award
Spring 2026
Abstract
Our understanding of the mechanisms and processes that occur in near-Earth space is gained through by new research enabled by advancements in technology, instrumentation, and analysis methods. This dissertation presents three advances for our ability to study near-Earth space. First, neutral winds govern how energy and momentum are transported through the mesosphere and thermosphere. Despite their importance, neutral winds are difficult to measure at these altitudes (~80-500 km) and remain the least characterized parameter of the upper atmosphere. To address this measurement gap, the Winds Cross-Track (WCT) instrument is developed to take high resolution in situ measurements of the neutral wind. A numerical model of the instrument response is developed to relate the measured signal structure to incident flow parameters. Wind profiles from its maiden flight demonstrate the capability of the WCT to take high fidelity wind velocity measurements with fine vertical resolution. Second, two sources dominate the energy deposition into the high-latitude lower ionosphere / thermosphere: Joule heating and precipitating energetic electrons. One goal of the Dissipation sounding rocket mission was to better quantify these energy sources. An onboard electrostatic analyzer (ESA) measured the distribution of precipitating electrons. The global airglow (GLOW) model is adapted to use these measurements as inputs to constrain the model output. The modeled conductivity profiles are combined with other measurements to derive Joule heating profiles. The energy flux from precipitating electrons is found to be significantly larger than the energy from Joule heating during the flight. Lastly, space plasma populations are distributed over a substantial range of densities, kinetic temperatures, and bulk velocities. Measuring the full range of plasma conditions for even one of these populations is difficult for current top-hat ESAs. A modification to the standard top-hat ESA design is developed that extends its differential energy flux dynamic range by up to three orders of magnitude. The design space of the modification is investigated through ion optics simulations. A prototype ESA is developed and tested, with laboratory results consistent with the behavior expected from simulation predictions.
Document Type
Dissertation
First Advisor
James Clemmons
Second Advisor
Christoforos Mouikis
Third Advisor
Lynn Kistler
Department or Program
Physics
Degree Name
Doctor of Philosophy
Recommended Citation
Davis, Lance, "Advancing Geospace Observation Capabilities for Thermospheric Neutral Winds, High-Latitude Energy Deposition, and Broad Plasma Conditions" (2026). Doctoral Dissertations. 3016.
https://scholars.unh.edu/dissertation/3016