Physics Commons^™

Using Natural Phenomena To Study The Ionosphere, Joseph Benjamin Malins

Physics & Astronomy ETDs

This dissertation explores novel techniques for observing the ionosphere using natural signals. The ionosphere is a region of plasma hundreds of kilometers above the Earth that affects communication and remote sensing applications across the world. Traditional techniques for observing the ionosphere involve using man made radio signals, either to reflect the signal at HF frequencies or to pass several signals through the ionosphere and compare the difference the ionosphere makes in the signals. However, such techniques are limited by the ability of equipment to produce these signals and by the numerous laws and regulations governing transmission of signals in the …

Non-Linear Magnetosphere-Ionosphere Interactions At High Latitudes, Beket Tulegenov

Doctoral Dissertations and Master's Theses

Non-linear, 3D electromagnetic coupling between the ionosphere and magnetosphere is investigated in this dissertation. The study is based on a non-linear, 3D, reduced magnetohydrodynamic model describing interaction between dispersive Alfven waves and the nightside high-latitude ionosphere. Results are presented from a numerical study of small-scale, intense magnetic field-aligned currents observed in the vicinity of the discrete auroral arc by the Magnetosphere-Ionosphere Coupling in the Alfven Resonator (MICA) sounding rocket launched from Poker Flat, Alaska, on 19 February 2012. The goal of the MICA project was to investigate the hypothesis that such currents can be produced inside the ionospheric Alfven resonator …

Planar Ion Probe For Low-Latitude Ionosphere/Thermosphere Enhancements In Density Cubesat Mission, Liam Owen Gunter

Doctoral Dissertations and Master's Theses

One of the crucial measurements for characterizing any space weather event is absolute plasma density and plasma density fluctuations, both spatially and temporally. Langmuir probes are the oldest and most proven instruments for these in-situ measurements. This thesis enumerates the development of a miniaturized low-noise Langmuir probe intended for a dual CubeSat mission to study equatorial temperature and wind anomaly in the Earth’s ionosphere.

The Langmuir probe instrument developed is of a planar geometry and fix biased in the ion saturation region, i.e. negative w.r.t. spacecraft chassis. Operating the Langmuir probe in the ion saturation region avoids excessive spacecraft charging …

Global Ionosonde And Gps Radio Occultation Sporadic-E Intensity And Height Comparison, Joshua Y. Gooch

Theses and Dissertations

A global, multi-year comparison of low and mid-latitude COSMIC GPS radio occultation (RO) sporadic-E (E_s) plasma frequency and altitude and Digisonde blanketing frequency (fbEs) and altitude within 150 km and 30 minutes of each other. RO methods used to estimate the intensity of the E_s layer include the scintillation index S4, total electron content (TEC) with both a constant and variable E_s cloud thickness, and an Abel transform. The S4 and TEC with varying thickness techniques both under-represent the fbEs values while the TEC with constant thickness and Abel transform better estimate Digisonde fbEs values. …

Modeling High-Altitude Nuclear Detonations Using Existing Ionospheric Models, Sophia G. Schwalbe

Theses and Dissertations

One threat to the United States is a nuclear weapon being detonated at high altitude over the country. The resulting electromagnetic pulse (EMP) could devastate the nation. Despite its destructive nature, the response of the ionosphere to such an event is poorly understood. This study assesses if existing ionospheric models, which are used to nowcast and forecast ionospheric changes, can be used to model the response to a high-altitude nuclear detonation (HAND). After comparing five ionosphere models, the Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIE-GCM) was selected and modified to incorporate an array of F10.7 indices to serve as a proxy for …