Open Access. Powered by Scholars. Published by Universities.®
- Discipline
- Keyword
-
- PEA (2)
- Atmosphere (1)
- Carbosurf+ (1)
- Charge deposition (1)
- Charge transport (1)
-
- Collisional processes (1)
- Colloquium (1)
- Computational methods (1)
- Computer methods (1)
- Conservation laws (1)
- Deep charging (1)
- Dielectric (1)
- Diffraction patterns (1)
- Diffraction spectra (1)
- Drift-kinetic theory (1)
- Earth's stable rotation rate (1)
- Electron beam (1)
- Ellipsoidal deformations (1)
- Embedded Charge Distributions (1)
- Equations of fluid dynamics (1)
- Fluid flows (1)
- Forces (1)
- GEO radiation environment (1)
- Geodetic model (1)
- Improvement (1)
- Inertial forces (1)
- Kinetics and dynamics (1)
- Lidar (1)
- Lithography (1)
- MIGHTI/ICON (1)
Articles 1 - 17 of 17
Full-Text Articles in Physics
Charge Transport In Dielectric: The Pulsed Electroacoustic Method, Zachary Gibson
Charge Transport In Dielectric: The Pulsed Electroacoustic Method, Zachary Gibson
Physics Student Research
Understanding and predicting charge accumulation and transport in dielectric materials is vital in applications where excess charge can accumulate including semiconductor devices, high-power electronic devices, high voltage DC cabling, high-energy physics facilities, plasma chambers, and spacecraft charging. Excess charge accumulation may result in electrostatic discharge events, which are the leading cause of spacecraft failure due to the space environment. The pulsed electroacoustic method allows you to “pop the hood” and non-destructively directly measure the embedded charge distributions in dielectric materials. Charge transport in disordered dielectric materials, measurements with the pulsed electroacoustic system, and comparison to models will be presented.
Geodetic Model For Teaching Motion On The Earth's Spheroidal Surface, Boyd F. Edwards, John M. Edwards
Geodetic Model For Teaching Motion On The Earth's Spheroidal Surface, Boyd F. Edwards, John M. Edwards
All Physics Faculty Publications
We explore the forces that shape our spheroidal Earth and the forces that govern the motion of a puck that slides without friction on its surface. The Earth's stable spheroidal shape (apart from small-scale surface features) is determined by balancing the gravitational forces that hold it together against the centrifugal forces that try to tear it apart. The motion of a puck on its surface differs profoundly from motion on a sphere because the Earth's spheroidal deformations neutralize the centrifugal and gravitational forces on the puck, leaving only the Coriolis force to govern the motion. Yet the Earth's spheroidal deformations …
Comparison Of Charge Deposition Profiles In Polymers Irradiated With Monoenergetic Electrons: Pulsed Electroacoustic Measurements And Af-Numit3 Modeling, Zachary Gibson, Jr Dennison, Brian Beecken
Comparison Of Charge Deposition Profiles In Polymers Irradiated With Monoenergetic Electrons: Pulsed Electroacoustic Measurements And Af-Numit3 Modeling, Zachary Gibson, Jr Dennison, Brian Beecken
Physics Student Research
Successful spacecraft design and charging mitigation techniques require precise and accurate knowledge of charge deposition profiles. This paper compares models of charge deposition and transport using a venerable deep dielectric charging code, AF-NUMIT3, with direct measurements of charge profiles via pulsed electroacoustic (PEA) measurements. Eight different simulations were performed for comparison to PEA experiments of samples irradiated by 50 keV or 80 keV monoenergetic electrons in vacuum and at room temperature. Two materials, polyether-ether ketone (PEEK) and polytetrafluoroethylene (PTFE), were chosen for their very low conductivities so that minimal charge migration would occur between irradiation and PEA measurements. PEEK was …
Embedded Charge Distributions In Electron Irradiated Polymers – Pulsed Electroacoustic Method Reproducibility And Calibration, Zachary Gibson, Jr Dennison, Ryan Hoffmann
Embedded Charge Distributions In Electron Irradiated Polymers – Pulsed Electroacoustic Method Reproducibility And Calibration, Zachary Gibson, Jr Dennison, Ryan Hoffmann
Physics Student Research
The pulsed electroacoustic (PEA) method has been used to measure the embedded charge distributions in electron irradiated polymers. The PEA method allows for non-destructive direct measurements of embedded charge distributions in dielectric materials. Samples of polyether-etherketone (PEEK) and polytetrafluoroethylene (PTFE) of 125 μm or 250 μm thickness were tested after irradiation with either a 50 keV or 80 keV electron beam. The reproducibility of the PEA method and the experimental conditions were studied by: (i) measuring each sample multiple times in a given mounting configuration, (ii) re-measuring each sample after repositioning them in the PEA test fixture, and (iii) measuring …
Pan-Antarctic Investigations Of Mesospheric Wave Dynamics And Influences Using The Angwin Network, Michael J. Taylor
Pan-Antarctic Investigations Of Mesospheric Wave Dynamics And Influences Using The Angwin Network, Michael J. Taylor
Funded Research Records
No abstract provided.
Forces And Conservation Laws For Motion On Our Spheroidal Earth, Boyd F. Edwards, John M. Edwards
Forces And Conservation Laws For Motion On Our Spheroidal Earth, Boyd F. Edwards, John M. Edwards
All Physics Faculty Publications
We explore the forces and conservation laws that govern the motion of a hockey puck that slides without friction on a smooth, rotating, self-gravitating spheroid. The earth's oblate spheroidal shape (apart from small-scale surface features) is determined by balancing the gravitational forces that hold it together against the centrifugal forces that try to tear it apart. The earth achieves this shape when the apparent gravitational force on the puck, defined as the vector sum of the gravitational and centrifugal forces, is perpendicular to the earth's surface at every point on the surface. Thus, the earth's spheroidal deformations neutralize the centrifugal …
Temperature Tides Across The Mid-Latitude Summer Turbopause Measured By A Sodium Lidar And Mighti/Icon, Tao Yuan, M. H. Stevens, C. R. Englert, T. J. Immel
Temperature Tides Across The Mid-Latitude Summer Turbopause Measured By A Sodium Lidar And Mighti/Icon, Tao Yuan, M. H. Stevens, C. R. Englert, T. J. Immel
All Physics Faculty Publications
Local full diurnal coverage of temperature variations across the turbopause (∼90–115 km altitude) is achieved by combining the nocturnal observations of a Sodium (Na) Doppler lidar on the Utah State University (USU) campus (41.7°N, 248.2°E) and NASA Michelson interferometer for global high-resolution thermospheric imaging (MIGHTI)/Ionospheric connection explorer (ICON) daytime observations made in the same vicinity. In this study, utilizing this hybrid data set during summer 2020 between June 12th and July 15th, we retrieve the temperature signatures of diurnal and semidiurnal tides in this region. The tidal amplitudes of both components have similar vertical variation with increasing altitude: less than …
Computational Frontiers In The Strong Gravity Regime, Maria Rodriguez
Computational Frontiers In The Strong Gravity Regime, Maria Rodriguez
Funded Research Records
No abstract provided.
Benchmarking Nimrod Continuum Kinetic Formulations Through The Steady-State Poloidal Flow, Joseph R. Jepson, Chris C. Hegna, Eric D. Held, J. Andrew Spencer, B. C. Lyons
Benchmarking Nimrod Continuum Kinetic Formulations Through The Steady-State Poloidal Flow, Joseph R. Jepson, Chris C. Hegna, Eric D. Held, J. Andrew Spencer, B. C. Lyons
All Physics Faculty Publications
In this work, continuum kinetic formulations are employed as a mechanism to include closure physics in an extended magnetohydrodynamics model. Two continuum kinetic approaches have been implemented in the plasma fluid code NIMROD [Sovinec et al., “Nonlinear magnetohydrodynamics with high-order finite elements,” J. Comput. Phys. 195, 355 (2004)] including a Chapman–Enskog-like (CEL) formulation and a more conventional δf approach. Ion kinetic closure schemes are employed to describe the neoclassical flow properties in axisymmetric toroidal geometry. In particular, predictions for steady-state values of poloidal flow profiles in tokamak geometry are provided using both the δf formulation and two different solution …
Phase-Space Dynamics Of Runaway Electrons In Tokamaks, Gavin Held
Phase-Space Dynamics Of Runaway Electrons In Tokamaks, Gavin Held
Physics Capstone Projects
Nuclear fusion converts the rest mass energy of ions like the deuteron and triton into kinetic energy. In theory, this energy can be harvested from a thermonuclear reactor to provide power outputs on the scale of 500 MW. High temperatures are needed for significant fusion to occur, hence the tokamak (a modern fusion confinement device) employs strong magnetic fields to keep the ionized gas (plasma) away from the tokamak wall. However, a problem that occasionally arises in a tokamak is that during a disruption an inductive electric field is created which can accelerate electrons to relativistic speeds (these electrons are …
The Effects Of Materials And Profiles Of Gratings On Diffraction Spectra, Brock Halling
The Effects Of Materials And Profiles Of Gratings On Diffraction Spectra, Brock Halling
Physics Capstone Projects
Diffraction patterns can be made either by transmitting or reflecting light from a grating which is an array of parallel lines (rulings) with a fixed periodicity. Elementary optical treatment of diffraction gratings only describes diffraction angles as a function of periodicity of the grating. However, we have observed that the profile and materials of the grating do affect the diffraction pattern. In this study, I investigated the correlation between the grating profiles obtained by scanning electron microscopy and the materials of the grating (polymer and silicon dioxide) and the spectra as a function of the diffraction angle. An optical spectrometer …
Developing Electron Beam Lithography At Nanoscale Device Laboratory, Din Pašić
Developing Electron Beam Lithography At Nanoscale Device Laboratory, Din Pašić
Physics Capstone Projects
At the Nanoscale Device Laboratory, we can routinely create patterns with a minimum linewidth of 800 nm using photolithography. However, to create photonic devices, the pattern size must be smaller than the wavelength of visible light (400 to 800 nm). Dedicated electron beam writers can achieve a sub-10 nm linewidth, but this system is beyond our reach. In this project, we plan to use a Nanometer Pattern Generation System connected to a Quanta 650 scanning electron microscope to perform e-beam lithography. After setting up a computer to run the NPGS system, and establishing communications with the SEM, we experimented with …
Comparisons Of Mesospheric Temperatures Between 70 And 110 Km: Usu Lidar, Nasa's Timed Satellite, And The Msis2 Empirical Model, David M. Collins
Comparisons Of Mesospheric Temperatures Between 70 And 110 Km: Usu Lidar, Nasa's Timed Satellite, And The Msis2 Empirical Model, David M. Collins
Physics Capstone Projects
Earth’s atmosphere can be characterized by its temperature structure, dividing the atmosphere into natural discrete regions. The mesosphere (50 to ~100 km) has been the least studied. Rayleigh-scatter lidars (RSL) and rockets can obtain local, high-resolution measurements above one spot, while satellites looking almost horizontally obtain global measurements. These two methods of measuring atmospheric conditions are compared using the USU RSL and the SABER instrument on NASA’s TIMED satellite. These measurements were graphed to show four sets of temperatures from several sources in the atmospheric region 70 km to 110 km above USU. The results show similar temperatures for many …
Improving Skills In Computer Methods: Introductory Toolkit To Python For Undergraduate Physics Majors, Erin O'Donnell, Melissa Rasmussen
Improving Skills In Computer Methods: Introductory Toolkit To Python For Undergraduate Physics Majors, Erin O'Donnell, Melissa Rasmussen
Physics Capstone Projects
The computer-based curriculum for undergraduate physics students before 2019 struggled to stay current and applicable. When the course was created in the early 2000s, MathCad was used daily by many physicists. As computer’s and their computational abilities have grown exponentially, so have programming languages and applications. Now in the late 2010s/early 2020s, Excel, Python, and Mathematica are some of the most common computer appliques. To address this, we created toolkits to give undergraduate physicists the experience for future classes, careers, and graduate school. This paper focuses on the process for creating the Python toolkit and overall class setup. Run on …
Ion Beam-Treated Space Polymers: Long-Term Stability In Geo-Simulated Environments, Jacob Kleiman, Zelina Iskanderova, Leonid Krishtein, J. R. Dennison, Brian Wood, Anatoly Grigorievsky, Carl Best
Ion Beam-Treated Space Polymers: Long-Term Stability In Geo-Simulated Environments, Jacob Kleiman, Zelina Iskanderova, Leonid Krishtein, J. R. Dennison, Brian Wood, Anatoly Grigorievsky, Carl Best
Journal Articles
As part of a large program conducted between years 2010 and 2018, a number of ion beam surface treatments and proprietary coatings formed on advanced space polymers by direct ion beam deposition were developed at Integrity Testing Laboratory (ITL) Inc, in Canada. Thistechnology allowed producing surfaces with controlled surface resistivity in a wide range of charge dissipation values, with negligibly low additional RF losses and other important functional properties, that allowed using such treated materials and products in modern space antennae, solar arrays and other external applications on spacecrafts in GEO environment. This paper will present an overview of results …
Rapid: Sodium (Na) Lidar Validation Of Mighti Daytime Temperature Observations Onboard Nasa Icon Satellite, Tao Yuan
Funded Research Records
No abstract provided.
Potential, Field, And Interactions Of Multipole Spheres: Coated Spherical Magnets, Jeong-Young Ji, Boyd F. Edwards, J. Andrew Spencer, Eric D. Held
Potential, Field, And Interactions Of Multipole Spheres: Coated Spherical Magnets, Jeong-Young Ji, Boyd F. Edwards, J. Andrew Spencer, Eric D. Held
All Physics Faculty Publications
We show that the energy, force, and torque between two spherically symmetric multipole density distributions are identical to those between two point multipoles, and apply this point-sphere equivalence to coated spherical dipole magnets. We also show that the potential and field of such a distribution are equivalent to those due to point multipoles located at the center of the distribution. We expand the inverse-distance potential in terms of harmonic (Hermite irreducible) tensors, whose properties enable us to express the potential energy, force, and torque for two arbitrary source distributions in a series of point-multipole interactions. This work generalizes recent work …