Geomagnetic micropulsations. ; Magnetosphere. ; Cosmic magnetic fields -- Measurement.
A study of magnetospheric pulsations is presented in three parts. The first consists of a statistical survey using data from the AMPTE/IRM satellite. A number of conclusions are drawn from the study. Evidence is provided that supports the theory...
This thesis presents two-fluid simulations of forced magnetic reconnection with finite electron inertia in two and three dimensional periodic systems. Reconnection in the system is driven by a spatially localized forcing function, added to the ion...
The ability to forecast the weather of the geospace environment depends critically on the ability to accurately model the dynamics of the coupled magnetosphere-ionosphere (MI) system. The MI interaction involves a set of electrodynamic and plasma...
Currently, the hypothesis that discrete auroral arcs are produced by fluxes of magnetospheric electrons accelerated along the ambient magnetic field into the ionosphere by linear/non-linear mechanisms associated with magnetic field-aligned currents...
Brain tissue mechanics are an important biomarker for neurological disorders, yet methods to obtain tissue information yield inconsistent conclusions. These techniques can be invasive or require excised tissue, where tissue function is altered from...
The purpose of this thesis is to describe methods for detecting hidden crevasses on glaciers in Polar regions. Crevasses form in ice sheets as a result of forces imposed upon the brittle ice. The crevasses are hidden from view by bridges of soft...
The fluxes of radiation belt electrons are highly variable, due to a competition between various acceleration, loss, and transport processes. Studies of any of the processes are equally important. My study focuses on electron-EMIC (electromagnetic...
The discovery of the Van Allen radiation belts in the 1958 was the first major discovery of the Space Age. There are two belts of energetic particles. The inner belt is very stable, but the outer belt is extremely variable, especially during...
Since their discovery in laboratory plasmas in the 1920s, Langmuir waves have been observed to be ubiquitous in plasma environments, particularly in space plasmas. From the greater solar wind to planetary foreshocks and the auroral ionosphere,...
Whistler-mode chorus waves have recently drawn tremendous attention as an important mechanism for controlling the energetic electron flux in Earth’s radiation belt. This dissertation aims to answer questions about whistler-mode chorus waves, such...
The resonant excitation of low-frequency MHD waves by energetic ring current ions has been studied by means of hybrid MHD-gyrokinetic particle simulations. The purpose of the investigation is to identify the instability mechanism for internally...
Van Allen radiation belts -- Mathematical models. ; Magnetosphere -- Mathematical models. ; Magnetohydrodynamics -- Mathematical models.
The physics of geomagnetically-trapped radiation has been a topic of interest since the discovery of the Van Allen belts in 1958. As the energetic particles comprising these belts can pose a hazard to human activity in space, considerable effort...
Van Allen radiation belts -- Mathematical models. Electrons -- Diffusion -- Mathematical models. Magnetohydrodynamic waves -- Mathematical models.
It is becoming increasingly important to understand the dynamics of radiation belt energetic particles given their potentially hazardous effects on satellites and our ever-increasing dependence on those satellites. There is a need to determine...
The thesis is devoted to the effects of electromagnetic coupling between the Earth's magnetosphere and the active auroral ionosphere. The research has been focused, in particular, on the concept of ionospheric feedback instability. The feedback...
Geology -- Guatemala -- Lake Atitlan area; Volcanism -- Guatemala -- Lake Atitlan area; Calderas -- Guatemala -- Lake Atitlan area.
Geological mapping, petrological and geophysical studies in the lake Atitlan area, Guatemala, have revealed four distinct periods of stratovolcano growth, each followed by major silicic eruptions and caldera collapse. The first period (12 - 11 my...
Loss processes greatly impact the dynamics of the Earth's radiation belts. In 1996, a balloon-borne germanium detector flown over Kiruna, Sweden detected the first terrestrial X-rays with energies on the order of 1 MeV. The spectrum for these...
Magnetosphere -- Mathematical models. Magnetic reconnection -- Mathematical models.
In this thesis we present the results of two studies of magnetic reconnection at the dayside magnetopause using the Lyon-Fedder-Mobarry magnetospheric simulation code. The first study examined the global properties of reconnection as a function of...
Experimental and theoretical aspects of macroscopic and mesoscopic elastic instability are investigated in this thesis. For the theoretical investigations we utilize a Lagrangian formulation of nonlinear continuum elasticity theory, the novel...
There is a renewed interest in the study of the radiation belts with the recent launch of the Van Allen Probes satellites. The mechanisms that drive the global response of the radiation belts to geomagnetic storms are not yet well understood....
Magnetic resonance elastography (MRE) is a technique to produce images of the mechanical properties of tissue, which are indicative of a variety of diseases. Tissue motions measured using MRI are used to solve an inverse problem to recover...