Open Access. Powered by Scholars. Published by Universities.^{®}
 Discipline
 Keyword

 Observations (2)
 Satellite (2)
 General Relativity and Quantum Cosmology (2)
 Polar cap arcs (2)
 Akebono (1)

 Critical (1)
 Backscatter (1)
 (e (1)
 Electrojet (1)
 Course design and evaluation (1)
 1STORDER (1)
 Beacon (1)
 Directions (1)
 Carbon (1)
 C60 (1)
 Classical field theory (1)
 Amorphous solid (1)
 AMORPHOUSCARBON (1)
 Crystalline solid (1)
 Conformal Group (1)
 CONVECTIVE INSTABILITIES (1)
 ELECTRONICPROPERTIES (1)
 CONVECTION (1)
 2e) Spectroscopy (1)
 Asymptotic conservation laws (1)
 And evaluation (1)
 Core Electron Binding Energy (1)
 Auroral (1)
 Autocatalytic (1)
 Array (1)
 Publication
 Publication Type
Articles 1  21 of 21
FullText Articles in Physics
Thermally Induced CoreElectron BindingEnergy Shifts In Transition Metals: An Experimentalinvestigation Of Ta(100), D. Mark Riffe, B. Kim, W. Hale, J. L. Erskine
Thermally Induced CoreElectron BindingEnergy Shifts In Transition Metals: An Experimentalinvestigation Of Ta(100), D. Mark Riffe, B. Kim, W. Hale, J. L. Erskine
All Physics Faculty Publications
Highresolution photoemission spectra from the 4f_{7/2} levels of Ta(100) have been obtained between 77 K and room temperature. The data show an increase in both the surface and bulk corelevel binding energies (BE’s) as the temperature is raised: between 77 and 293 K the bulk and surface BE’s increase by 31±3 and 13±2 meV, respectively. A model calculation of the bulk bindingenergy increase, which is based upon the lattice expansion of the solid, is in good agreement with the experimental results and indicates that the shifts arise from both initial and finalstate effects ...
Auroral Electrojet Irregularity Theory And Experiment: A Criticalreview Of Present Understanding And Future Directions, J. D. Sahr, Bela G. Fejer
Auroral Electrojet Irregularity Theory And Experiment: A Criticalreview Of Present Understanding And Future Directions, J. D. Sahr, Bela G. Fejer
Bela G. Fejer
We review the experimental observations of meter scale plasma irregularities in the auroral E region and the status of their theoretical understanding. Most of the experimental data is derived from VHF radar scatter experiments, but sounding rockets also provide crucial information not obtainable from radars. Linear theories correctly predict the altitude of occurence, strong magnetic aspect sensitivity, marginal instability, and typical phase velocities. Subsequent nonlinear theories have been developed to account for other observed features but with less satisfying application. Further understanding of auroral electrojet irregularities is impeded by precision limitations of existing instruments, by radar data which may seem ...
Building A Competition Buzzer Set, Jr Dennison, Richard Davis
Building A Competition Buzzer Set, Jr Dennison, Richard Davis
All Physics Faculty Publications
No abstract provided.
Asymptotic Conservation Laws In Field Theory, Ian M. Anderson, Charles G. Torre
Asymptotic Conservation Laws In Field Theory, Ian M. Anderson, Charles G. Torre
All Physics Faculty Publications
A new, general, field theoretic approach to the derivation of asymptotic conservation laws is presented. In this approach asymptotic conservation laws are constructed directly from the field equations according to a universal prescription which does not rely upon the existence of Noether identities or any Lagrangian or Hamiltonian formalisms. The resulting general expressions of the conservation laws enjoy important invariance properties and synthesize all known asymptotic conservation laws, such as the ArnowittDeserMisner energy in general relativity.
Raman Spectroscopy Of Carbon Materials, Jr Dennison, M. Holtz, G. Swain
Raman Spectroscopy Of Carbon Materials, Jr Dennison, M. Holtz, G. Swain
All Physics Faculty Publications
Use of carbon materials is no longer limited to diamond jewelry or graphite pencils and lubricants. The last decade has witnessed an explosion of technological applications driven by the development of fabrication methods and the discovery of several new classes of pure carbon. Structural diversity exhibited by the carbon atoms, from local chemical order to longrange crystalline order, is key to understanding their physical and chemical properties and in future materials development. This article summarizes the use of Raman spectroscopy as a principal tool to investigate the vibrational dynamics of carbon materials and to provide indirect structural characterization of their ...
Observationsof InnerPlasmasphere Irregularities With A Satellite Beacon Interferometer Array, A. R. Jacobsen, G. Hogeveen, R. C. Carlos, G. Wu, Bela G. Fejer, M. C. Kelley
Observationsof InnerPlasmasphere Irregularities With A Satellite Beacon Interferometer Array, A. R. Jacobsen, G. Hogeveen, R. C. Carlos, G. Wu, Bela G. Fejer, M. C. Kelley
Bela G. Fejer
A radiointerferometer array illuminated by 136MHz beacons of several geosynchronous satellites has been used to study small (≥ 1013 m−2) transient disturbances in the total electron content along the lines of sight to the satellites. Highfrequency (ƒ> 3 mHz) electron content oscillations are persistently observed, particularly during night and particularly during geomagnetically disturbed periods. The oscillations move across the array plane at speeds in the range 200–2000 m/s, with propagation azimuths that are strongly peaked in lobes toward the western halfplane. Detailed analysis of this azimuth behavior, involving comparison between observations on various satellite positions, indicates compellingly that ...
Pattern Formation And Evolution Near Autocatalytic Reaction Fronts In A Narrow Vertical Slab, J. Huang, Boyd F. Edwards
Pattern Formation And Evolution Near Autocatalytic Reaction Fronts In A Narrow Vertical Slab, J. Huang, Boyd F. Edwards
All Physics Faculty Publications
Linear analysis and nonlinear numerical simulations of autocatalytic reaction fronts ascending in narrow vertically unbounded slabs describe the growth, development, and annihilation of fingers in the front, the dynamics of edge suppression, and a secondary transition to a tworoll state above the onset of convection. The pattern formation and evolution of the reaction fronts are determined by the horizontal aspect ratio Γ=b/a and the dimensionless driving parameter S=δga^{3}/νD_{C}, which involve the gap thickness a, the slab width b, the fractional density difference δ between the unreacted and reacted solutions, the gravitational acceleration g, the ...
Application Of (E,2e) Spectroscopy To The Electronic Structure Of Valence Electrons In Crystalline And Amorphous Solids, Jr Dennison, A. L. Ritter
Application Of (E,2e) Spectroscopy To The Electronic Structure Of Valence Electrons In Crystalline And Amorphous Solids, Jr Dennison, A. L. Ritter
All Physics Faculty Publications
This review presents theoretical and experimental aspects of (e,2e) spectroscopy specific to the study of crystalline and amorphous solids. The cross section for (e,2e) scattering is proportional to the spectral momentum density of the ejected electron under certain approximations. The theoretical framework for interpreting (e,2e) measurements is summarized here and general properties of the spectral momentum density of solids are discussed. Different designs of the (e,2e) spectrometer are described and sample preparation techniques are briefly reviewed. A summary of (e,2e) experiments on the electronic structure of valence electrons in graphite, ion sputtered and evaporated amorphous ...
Incoherent Scatter Radar, Ionosonde,And Satellite Measurements Of Equatorial F Region Vertical Plasma Drifts In The Evening Sector, Bela G. Fejer, E. R. De Paula, L. Scherliess, I. S. Batista
Incoherent Scatter Radar, Ionosonde,And Satellite Measurements Of Equatorial F Region Vertical Plasma Drifts In The Evening Sector, Bela G. Fejer, E. R. De Paula, L. Scherliess, I. S. Batista
Bela G. Fejer
Studies of equatorial F region evening vertical plasma drifts using different measurement techniques have produced conflicting results. We examine the relationship of incoherent scatter radar and ionosonde drift observations over the Peruvian equatorial region, and AEE satellite drifts for different geophysical conditions. Our data show that there is large daytoday variability on the ratios of radar and ionosonde drifts, but on the average the measurements from these two techniques are in fair agreement during low and moderate solar flux conditions. For high solar activity, however, the Jicamarca evening drifts during equinox and December solstice are significantly larger than the ionosonde ...
A Study Of The Gradient Drift Instability In The HighLatitude Ionosphere Using The Utah State University Time Dependent Ionospheric Model, Mahesh Subramanium
A Study Of The Gradient Drift Instability In The HighLatitude Ionosphere Using The Utah State University Time Dependent Ionospheric Model, Mahesh Subramanium
All Graduate Theses and Dissertations
Research over the years has established that the Gradient Drift Instability process causes smallscale irregularities, mostly along the edges of the highlatitude polar cap patches. Studying these irregularities will help in the development of a global Scale Ionospheric model, which is a central part of a global space weather forecast system. Much theoretical work has been done with varying degrees of complexity to study this instability in the high latitude patches.
In this work we have used the Utah State University Time Dependent Ionospheric Model to model the highlatitude patches, calculate the growth rate of the instability, and perform a ...
An Instrument For Experimental Secondary Electron Emission Investigations, With Application To The Spacecraft Charging Problem, Robert Davies
An Instrument For Experimental Secondary Electron Emission Investigations, With Application To The Spacecraft Charging Problem, Robert Davies
All Graduate Theses and Dissertations
Secondary electron emission (SEE) and incidentparticle backscattering are important processes accompanying the impact of energetic electrons and ions on surfaces. The phenomena play a key role in the buildup of electrical charge on spacecraft surfaces, and are therefore of particular interest to scientists attempting to model spacecraft charging. In response to a demonstrated need for data, techniques for determining total secondary electron (SE) and backscatter (BS) yields (del) and (neu), and associated scatteringangleresolved,scatteringenergyresolved, and simultaneous angleenergyresolved yields have been developed. Further, an apparatus capable of making the necessary measurements for experimental determination of these quantitiesfor conducting materials in an ...
Chemical Wave Propagation In HeleShaw Cells And Porous Media, D. A. Vasquez, J. W. Wilder, Boyd F. Edwards
Chemical Wave Propagation In HeleShaw Cells And Porous Media, D. A. Vasquez, J. W. Wilder, Boyd F. Edwards
All Physics Faculty Publications
Chemical waves induce density gradients in fluids which may lead to convection. This paper studies the convective effects on chemical waves propagating in porous media or in fluids confined between two parallel vertical walls. Chemical waves in the iodate–arsenous acid system are modeled with a one variable reaction‐diffusion equation. The fluid flow is modeled using Darcy’s law. A linear stability analysis on convectionless fronts shows a transition to convection. The full nonlinear equations describing the convective front are solved numerically on a vertical slab. Convective fronts propagate faster than convectionless fronts. Near the onset of convection, the ...
Asymptotic Conservation Laws In Classical Field Theory, Ian M. Anderson, Charles G. Torre
Asymptotic Conservation Laws In Classical Field Theory, Ian M. Anderson, Charles G. Torre
Mathematics and Statistics Faculty Publications
A new, general, field theoretic approach to the derivation of asymptotic conservation laws is presented. In this approach asymptotic conservation laws are constructed directly from the field equations according to a universal prescription which does not rely upon the existence of Noether identities or any Lagrangian or Hamiltonian formalisms. The resulting general expressions of the conservation laws enjoy important invariance properties and synthesize all known asymptotic conservation laws, such as the ArnowittDeserMisner energy in general relativity.
Application Of (E,2e) Spectroscopy To The Electronic Structure Of Valence Electrons In Crystalline And Amorphous Solids, Jr Dennison, A. L. Ritter
Application Of (E,2e) Spectroscopy To The Electronic Structure Of Valence Electrons In Crystalline And Amorphous Solids, Jr Dennison, A. L. Ritter
Journal Articles
This review presents theoretical and experimental aspects of (e,2e) spectroscopy specific to the study of crystalline and amorphous solids. The cross section for (e,2e) scattering is proportional to the spectral momentum density of the ejected electron under certain approximations. The theoretical framework for interpreting (e,2e) measurements is summarized here and general properties of the spectral momentum density of solids are discussed. Different designs of the (e,2e) spectrometer are described and sample preparation techniques are briefly reviewed. A summary of recent (e,2e) experiments on the electronic structure of valence electrons in graphite, ion sputtered and evaporated ...
Raman Spectroscopy Of Carbon Materials, Jr Dennison, Mark Holtz, Greg Swain
Raman Spectroscopy Of Carbon Materials, Jr Dennison, Mark Holtz, Greg Swain
Journal Articles
Use of carbon materials is no longer limited to diamond jewelry or graphite pencils and lubricants. The last decade has witnessed an explosion of technological applications driven by the development of fabrication methods and the discovery of several new classes of pure carbon. Structural diversity exhibited by the carbon atoms, from local chemical order to longrange crystalline order, is key to understanding their physical and chemical properties and in future materials development. This article summarizes the use of Raman spectroscopy as a principal tool to investigate the vibrational dynamics of carbon materials and to provide indirect structural characterization of their ...
Relationship Of Theoretical Patch Climatology To Polar Cap Patch Observations, M. D. Bowline, Jan Josef Sojka, R. W. Schunk
Relationship Of Theoretical Patch Climatology To Polar Cap Patch Observations, M. D. Bowline, Jan Josef Sojka, R. W. Schunk
All Physics Faculty Publications
During a southward orientation of the interplanetary magnetic field (IMF), patches are often observed moving antisunward across the polar cap. In saying “patches” we refer to structures in which the F region electron densities are enhanced relative to lower background levels; we do not in this paper consider patches which are observed optically (see J. J. Sojka et al., Ambiguity in identificiation of polar cap F region patches, submitted to the Journal of Atmospheric and Terrestrial Physics, 1995). The patches can be modeled by a process which involves the “chopping up” of the tongue of ionization (TOI) [Sojka et al ...
ScaleInvariant Phase Space And The Conformal Group, James Thomas Wheeler
ScaleInvariant Phase Space And The Conformal Group, James Thomas Wheeler
All Physics Faculty Publications
The gauge bundle of the 4dim conformal group over an 8dim base space, called biconformal space, is shown have a consistent interpretation as a scaleinvariant phase space. Specifically, we show that a classical Hamiltonian system generates a differential geometry which is necessarily biconformal, and that the classical Hamiltonian dynamics of a point particle is equivalent to the specification of a 7dim hypersurface in flat biconformal space together with the consequent necessary existence of a set of preferred curves. The result is centrally important for establishing the physical interpretation of conformal gauging.
Internal Time Formalism For Spacetimes With Two Killing Vectors, Joseph D. Romano, Charles G. Torre
Internal Time Formalism For Spacetimes With Two Killing Vectors, Joseph D. Romano, Charles G. Torre
All Physics Faculty Publications
The Hamiltonian structure of spacetimes with two commuting Killing vector fields is analyzed for the purpose of addressing the various problems of time that arise in canonical gravity. Two specific models are considered: (i) cylindrically symmetric spacetimes, and (ii) toroidally symmetric spacetimes, which respectively involve open and closed universe boundary conditions. For each model canonical variables which can be used to identify points of space and instants of time, {\it i.e.}, internally defined spacetime coordinates, are identified. To do this it is necessary to extend the usual ADM phase space by a finite number of degrees of freedom. Canonical ...
Resonance Lidar To Study Temperatures, Winds, And Metal Densities In The Upper Mesosphere And Lower Thermosphere, Vincent B. Wickwar, T D. Wilkerson, D Rees, S C. Collins
Resonance Lidar To Study Temperatures, Winds, And Metal Densities In The Upper Mesosphere And Lower Thermosphere, Vincent B. Wickwar, T D. Wilkerson, D Rees, S C. Collins
All Physics Faculty Publications
None available.
Multiple Polar Cap Arcs: Akebono (Exos D) Observations, T. Obara, T. Mukai, H. Hayakawa, K. Tsurda, A. Matsuoka, A. Nishida, H. Fukunishi, L. Zhu, Jan Josef Sojka, D. J. Crain
Multiple Polar Cap Arcs: Akebono (Exos D) Observations, T. Obara, T. Mukai, H. Hayakawa, K. Tsurda, A. Matsuoka, A. Nishida, H. Fukunishi, L. Zhu, Jan Josef Sojka, D. J. Crain
All Physics Faculty Publications
Akebono (Exos D) observations demonstrate that polar cap arcs sometimes have a fine structure, that is, multiple (double or triple) arcs with spacing of a few tens of kilometers. The multiple polar cap arcs are dominantly observed in the nightside polar cap region, suggesting that low background conductance favors the appearance of the structured arcs. A relationship between the spacing and the average energy of the precipitating electrons is investigated. Results show that a higher energy leads to a wider spacing. Akebono observations also show the existence of a downward current region embedded between upward current regions (arcs). Comparison of ...
ModelObservation Comparison Study Of Multiple Polar Cap Arcs, Lie Zhu, Cesar E. Valladares, Jan Josef Sojka, Robert W. Schunk, D. J. Crain
ModelObservation Comparison Study Of Multiple Polar Cap Arcs, Lie Zhu, Cesar E. Valladares, Jan Josef Sojka, Robert W. Schunk, D. J. Crain
All Physics Faculty Publications
A quantitative modelobservation comparison of multiple polar cap arcs has been conducted by using a timedependent theoretical model of polar cap arcs. In particular, the electrodynamical features of multiple polar cap arcs with various spacings are simulated and the results are compared with the images obtained from the AllSky Intensified Photometer at Qaanaaq. The results show that the observed and simulated arcs are quite similar, both spatially and temporally. The results support the theory proposed by Zhu et al. [1993a, 1994b] that the structure of polar cap arcs is mainly determined by the magnetosphereionosphere (MI) coupling processes and that the ...