Physics Commons^™

Unified Model Of Charge Transport In Insulating Polymeric Materials, Alec Sim

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Charge transport, charging, and subsequent electrostatic discharge due to interactions with the space environment are primary concerns of spacecraft designers. Developing a physical understanding of the interactions of charge with the multitude of materials that spacecraft are composed of is a critical step in understanding and mitigating both short-term and long-term spacecraft degradation. In particular, the study of charge transport in highly insulating materials is critical as they store charge longer, with higher capacity, and with greater destructive capability than other materials.

The Utah State University Materials Physics Group, with the funding of the NASA James Webb Space Telescope project …

Carrier Dynamics In Ingaas/Gaas Quantum Dots Excited By Femtosecond Laser Pulses, Kripa Nidhan Chauhan

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In semiconductors, everything is becoming smaller day by day; quantum dots are the smallest nanomaterials available today. Typical sizes of these quantum dots are in the range of 5 to 30 nm in diameter. Variations in size changes many material properties, such as electrical and nonlinear optical properties, making them very different from bulk semiconductors. The size of the QDs results in new quantum phenomena, which yield some extraordinary properties. Material properties change dramatically because quantum effects arise from the confinement of electrons and holes in the material. Hence, semiconductor quantum dots play an important role in designing new devices …

Weyl Gravity As A Gauge Theory, Juan Teancum Trujillo

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A gauge theory is a theory in which the governing functional, known as the action, remains invariant under a continuous group of local transformations that form its symmetry. Each of the known fundamental interactions in the universe, such as electricity and magnetism, can be explained as arising from a particular gauge theory. Gravitation is no exception. Just as calculus can be used to find the value of a variable that maximizes or minimizes a function, calculus of variations can be used to find the equations, known as the field equations, that extremize the action, and these are the main equations …

Parallel Heat Transport In Magnetized Plasma, Mukta Sharma

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A huge global increase in energy use is inevitable, so there is an urgent need to seek cleaner ways of producing energy on large scales. Fusion is the energy source of the universe and a promising way to fulfill energy needs of mankind for many centuries to come. It offers important advantages as a safe, sustainable, and environmentally friendly source of energy. The International Thermonuclear Experimental Reactor (ITER) aims to demonstrate magnetic fusion is an energy source of the future. The goal of ITER is to produce 500 MW of fusion power given 50 MW of input power—or ten times …

Measurements Of The Temperature Dependence Of Radiation Induced Conductivity In Polymeric Dielectrics, Jodie Corbridge Gillespie

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Radiation Induced Conductivity (RIC) is the change in conductivity of a material due to bombardment from incident high energy radiation. This study is to determine the effect of RIC and RIC's temperature dependence in polymeric dielectrics, specifically Kapton HN, Kapton E, PTFE Teflon, Tefzel, and Low Density Polyethylene (LDPE). Interest in these materials arises from applications for use in future spacecraft, specifically the James Webb Space Telescope (JWST).

One major issue in the design of JWST, as in all spacecraft, is the charging and arcing of exposed materials, resulting in fatal damage to the electronics and/or the craft itself. Particles …

Lunar Tidal Effects In The Electrodynamics Of The Low-Latitude Ionosphere, Brian David Tracy

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In order to model and perform better forecasts of the upper atmosphere, we have studied variations in the equatorial ionosphere due to lunar tidal forcing. We used extensive measurements made by the Jicamarca Unattended Long-Term Investigations of the Ionosphere and Atmosphere (JULIA) and Incoherent Scatter Radar (ISR) systems at Jicamarca, Peru during geomagnetic quiet conditions to determine the season, local time, and lunar age-dependent lunar tidal effects on equatorial vertical plasma drifts. The amplitudes and phases of the semimonthly and monthly lunar tidal perturbations were derived using a least squares method. Our results indicate that, as expected, lunar tidal effects …

A Numerical Algorithm For Simulating Two Species Plasma, Richard F. Datwyler

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In our ever-growing technology-dependent society, a great need for cleaner, more lucrative energy sources is being sought out. Nuclear fission power plants have been used to help provide energy for many years now. More recently, fusion test reactors have been built and planned as another means to fill the energy quota. A large part of understanding the fundamental principles in a fusion reactor focuses on the principles of plasma physics. This topic of plasma physics has been studied for many decades and much progress has been made in its understanding.

More recently, computers have become larger and faster allowing for …

Particle Dynamics And Resistivity Characteristics In Bifurcated Current Sheets, Tushar Andriyas

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Charged particle chaos and its collective effects in different magnetic geometries are investigated in a sequence of various numerical experiments. The fields generated by the particles as a result of interaction with the background electric and magnetic fields is not accounted for in the simulation. An X-line is first used to describe the geometry of the magnetotail prior to magnetic reconnection and a study of the behavior of charged particles is done from a microscopic viewpoint. Another important geometry in the magnetotail prior to substorm onset is Bifurcated Current Sheet. The same analysis is done for this configuration. The existence …