Physical Sciences and Mathematics Commons^™

A Theoretical F Region Study Of Ion Compositional And Temperature Variations In Response To Magnetospheric Storm Inputs, Jan Josef Sojka, Robert W. Schunk

All Physics Faculty Publications

The response of the polar ionosphere to magnetospheric storm inputs was modeled. During the “storm,” the spatial extent of the auroral oval, the intensity of the precipitating auroral electron energy flux, and the plasma convection pattern were varied with time. The convection pattern changed from a symmetric two-cell pattern with a 20-kV cross-tail potential to an asymmetric two-cell pattern with enhanced plasma flow in the dusk sector and a total cross-tail potential of 90 kV. During the storm there were significant changes in the ion temperature, ion composition, and molecular/atomic ion transition height. The storm time asymmetric convection pattern produced …

Sondrestrom Overview, Vincent B. Wickwar, J D. Kelly, O De La Beaujardiere, C A. Leger, F Steenstrup, C H. Dawson

All Physics Faculty Publications

This overview of the Sondrestrom radar provides background material to help understand the early scientific results discussed in the following series of papers. It describes the geophysical region probed by the radar, the data acquisition procedure, and the extensive set of physical parameters derived.

The Polar Ionosphere: Editorial, Vincent B. Wickwar, J W. Meriwether Jr.

All Physics Faculty Publications

Editorial

Initial Millstone Hill, Sondrestrom, And Hilat Observations Of Thermospheric Temperatures And Frictional Heating, W L. Oliver, J C. Foster, J M. Holt, G B. Loriot, Vincent B. Wickwar, J D. Kelly, O De La Beaujardiere, P F. Bythrow, D I. Meng, F J. Rich, R E. Huffman

All Physics Faculty Publications

Elevation scan observations made by the Millstone Hill and Sondrestrom incoherent scatter radars are combined to provide extended latitudinal coverage of thermospheric measurements. Maps of the latitudinal and temporal structure of the exospheric temperature are presented for two 24‐hour periods over the latitude range 45 to 72 degrees north. On the magnetically quiet June day the Millstone and Sondrestrom data formed a consistent picture of thermospheric structure. On the disturbed July day the two radars observed very different behavior, with Millstone Hill observing strong, long‐lived ion frictional heating events but Sondrestrom observing more quiescent behavior. Comparison with HILAT satellite data …

Plasma Characteristics Of Polar Cap F-Layer Arcs, H C. Carlson Jr., Vincent B. Wickwar, E J. Weber, J Buchau, J G. Moore, W Whiting

All Physics Faculty Publications

First results are reported of a comprehensive campaign to measure ionospheric structure and dynamics of nighttime polar cap F‐layer or F‐region arcs. Airborne optical and digital ionosonde data were collected simultaneously with ground based incoherent scatter radar data, continuously over many hours in time and 500 to 1000 km in space. Polar cap F‐region sub‐visual auroral arcs, which are commonly observed during quiet magnetic conditions, are found to represent boundaries (or shears) in the polar cap plasma circulation pattern. F‐region electron concentration enhancements are found in these features and can be of significance to polar thermospheric circulation, composition, and thermal …

The Meridional Thermospheric Neutral Wind Measured By Radar And Optical Techniques In The Auroral Region, Vincent B. Wickwar, J W. Meriwether Jr., P B. Hays, A F. Nagy

All Physics Faculty Publications

Radar observations of ion velocities in the magnetic zenith over Chatanika, Alaska, were used to determine the geomagnetic meridional component of the thermospheric neutral wind. Corrections for molecular diffusion and molecular ion contamination of the pure O⁺ composition assumed for the ionosphere were included in the analysis. Comparison of the averaged diurnal variation of the meridional wind showed good agreement between the two measurement techniques. Good agreement was also found for several cases of simultaneous observations. The evidence suggested that differences were caused by gravity waves. The 7 years of radar meridional wind results were examined with respect to …

Pitch Angle Properties Of Magnetospheric Thermal Protons And Satellite Sheath Interference In Their Observation, Jan Josef Sojka, G. L. Wrenn, J.F. E. Johnson

All Physics Faculty Publications

Cold proton observations from the geosynchronous GEOS 2 satellite are presented to show the pitch angle distribution of the refilling cold ion population found beyond the plasmapause. This refilling cold ion population flows into the depleted equatorial regions of the flux tubes from the topside ionosphere. This refilling is observed both day and night. The ions have energies between 0.5 and 3 eV. These energy characteristics are consistent with other recent observations. Although the observed angular distribution of these ions is highly complex, when allowance is made for the satellite sheath several conclusions can be made concerning the ion pitch …

Nighttime Thermospheric Winds Over Sondre Stromfjord, Greenland, J W. Meriwether Jr., P Shih, T L. Killeen, Vincent B. Wickwar, R G. Roble

All Physics Faculty Publications

Observations of nighttime thermospheric neutral winds made at Sondre Stromfjord, Greenland, with optical and radar instrumentation, showed an occasional abatement in the equatorward meridional wind at a magnetic local time corresponding to the nighttime division between the evening and morning convection cells. This abatement appeared primarily in the poleward observations. In contrast, however, the characteristic midnight “surge” was usually seen in the equatorward set of observations. The apparent acceleration of about 250 m/s or greater within 4.6° latitude we attribute, in part, to a merging of neutral jet streams generated by polar cap ion drag adjacent to the auroral zone …

Electric Field And Plasma Density Measurements In The Auroral Electrojet, R. Pfaff, M. C. Kelley, Bela G. Fejer, E. Kudeki, C. W. Carlson, A. Pedersen, B. Hausler

Bela G. Fejer

Intense electrostatic waves in the auroral E region have been detected simultaneously on two payloads launched in a mother-daughter configuration from Kiruna, Sweden. The data sets comprise electric field and density measurements from the ambient (dc) conditions to fluctuations as high as 50 kHz. The dc electric field measured by both payloads was 54 mV/m northwest, which corresponded to an electron drift velocity of 1080 m/s. This electric field drove two-stream waves perpendicular to both B and E observed by both spacecraft throughout an altitude region which agrees quite well with the range predicted by linear two-stream theory. The power …

Ion Cyclotron Waves As Apossible Source Of Resonant Auroral Radar Echoes, Bela G. Fejer, R. W. Reed, D. T. Farley, W. E. Swartz, M. C. Kelley

Bela G. Fejer

Auroral backscatter radar observations were made from Ithaca, New York, at 50 MHz during the early morning of April 1, 1976, a period of high magnetic disturbance (Kp ∼ 8). The backscattered power showed large rapid (time scale of a few minutes or less) variations, characteristic of discrete radar aurora, from L = 3.5–4. Doppler spectra of waves propagating in nearly the north-south direction from up to 28 different ranges were obtained simultaneously with good spatial (7.5 km) and temporal (2 s) resolution. Some unusual spectra with very narrow peaks at Doppler shifts between about 70 and 90 Hz were …

Directional And Dynamic Variations Ofauroral Power Spectra Related To The Ionospheric Electron Drift Velocity, E. Nielsen, C. I. Haldoupis, Bela G. Fejer, H. M. Ierkic

Bela G. Fejer

Power spectral observations of auroral electron density fluctuations with a scale length of nearly 1 m have been made with the STARE system (Scandinavian twin auroral radar experiment). Simultaneous measurements of the mean radial Doppler velocities were used to derive estimates of the ionospheric electron drift velocity. The data were analyzed to determine the spectral dependence on the magnitude and direction of the electron drift velocity. The two spectral types, characterized as “narrow” and “broad,” were observed simultaneously from the same scattering volume. The width of the broad spectrum (up to about 1200 Hz) can be at least 3 times …

Theory Of Plasma Waves In The Auroral E-Region, Bela G. Fejer, J. Providakes, D. T. Farley

Bela G. Fejer

We have extended the linear fluid theory of electrojet plasma waves to the region where ion magnetization effects are important. Our general dispersion relation includes the effect of cross-field and field-aligned drifts, ion inertia, electron density gradients, and recombination. In the absence of density gradients and recombinational damping, the oscillation frequency at marginal instability is changed by the ion magnetization effects from the ion acoustic frequency, ω = kCs, to the modified ion cyclotron frequency ω² = Ωi² + k²Cs². These upper E region waves can be driven by field-aligned and/or cross-field drifts and have the smallest threshold drift velocities …

Underwater Acoustic Wavefront Phase Fluctuations, George L. Vojtech Jr.

OES Theses and Dissertations

In conventional underwater acoustics sound propagation is generally modeled and applied as a coherent or incoherent process. This paper addresses a relatively new theory, that of a range driven increasingly incoherent ray propagation through a real ocean environment, Possible mechanisms are discussed and experimental data presented to reinforce the theory.

Dipole Moment And Potential Energy Functions Of The X ¹Σ + And A 1Σ+ States Of Nah, W. T. Zemke, Ronald E. Olson, K. K. Verma, W. C. Stwalley, B. Liu

Physics Faculty Research & Creative Works

Calculated radiative transition probabilities between all vibrational levels in the X 1Σ+ state (υ=0-21) and in the A 1Σ+ state (υ=0-32) of NaH are given. In addition, the calculated spontaneous emission lifetimes for vibrational- rotational levels (J=0,1) and the calculated dipole moments for these same levels are given. The calculations use new hybrid potential energy curves based on Rydberg-Klein-Rees (RKR) and ab initio potential curves. The RKR curve for the X state is new. The calculations use new ab initio dipole moment functions of internuclear distance. © 1984 American Institute of Physics.

Resonant Electron Transfer And Excitation In Two-, Three-, And Four- Electron Caq +20 And Vq +23 Ions Colliding With Helium, J. A. Tanis, E. M. Bernstein, W. G. Graham, M. P. Stockli, M. Clark, Robert H. Mcfarland, T. J. Morgan, K. H. Berkner, A. S. Schlachter, J. W. Stearns

Physics Faculty Research & Creative Works

Significant new evidence is reported for resonant transfer and excitation in ion-atom collisions. This process, which is analogous to dielectronic recombination, occurs when a target electron is captured simultaneously with the excitation of the projectile followed by photon emission. Strong resonant behavior with structure, in agreement with theoretical calculations, is observed in the cross section for projectile K x rays coincident with single electron capture for 100-360-MeV Ca16+,17+,18+20 and 180-460-MeV V19+,20+,21+23 ions colliding with helium. © 1984 The American Physical Society.

Molecular-State Cross-Section Calculations For H+Csh-+Cs+, Ronald E. Olson, M. Kimura, H. Sato

Physics Faculty Research & Creative Works

Pseudopotential molecular-structure calculations have been used to obtain the seven lowest 1 and 1 states of CsH. These states and their associated radial and rotational coupling terms have been used to calculate the cross sections for H-+Cs+ ion-pair production in H+Cs(6s) and H+Cs*(6p) collisions at energies from 0.1 to 10 keV. The ion-ion mutual neutralization cross section, H-+Cs+ H+Cs, is also presented. The cross-section calculations were done with the perturbed-stationary-state method, modified to include two-electron translation factors. The ion-pair production cross section for ground-state reactants is in good agreement with experiment; collisions of H with excited Cs*(6p) show an order-of-magnitude …

The Homogeneous Nucleation Of Nonane, G. W. Adams, John L. Schmitt, R. A. Zalabsky

Physics Faculty Research & Creative Works

The homogeneous nucleation rate of n-nonane has been measured as a function of temperature and supersaturation ratio in a precision fast-expansion chamber. The measured nucleation rate ranges from 102 to 105 drops/cm3 over the temperature range 215-270 K. The results have been compared to the classical theory and to the classical theory with the RKC replacement factor. The RKC theory functional form is the basis for an empirical rate equation to fit the data. A full listing of the thermodynamic constants used for the reduction of the data is given. © 1984 American Institute of Physics.

Nuclear-Spin-Relaxation Study Of Internal Motion In Two Organic Molecular Solids, Alfonso M. Albano, Peter A. Beckmann, M. E. Carrington, E. E. Fisch, F. A. Fusco, A. E. O'Neill, Mary E. Scott

Physics Faculty Research and Scholarship

We investigate proton spin-lattice relaxation in two powdered organic molecular solids with reorienting methyl (CH3) and tert-butyl [C(CH3)3] groups: 3,5-di-tert-butylphenol (DTBP) and 1,3,5-tri-tert-butylbenzene (TTBZ). The temperature and Larmor frequency dependence of the relaxation rate is considerably more complicated than would be expected on the basis of random reorientations of the CH3 and C(CH3)3 groups. The spectral densities describing the relaxation are broader, and show more structure, than those customarily used to interpret relaxation data. Assuming that the spectral densities may be expressed as linear superpositions of Lorentzians, we are able to obtain a single, nonexponential correlation function which leads to …

The Effects On Plant Growth, W M. Porter, J. S. Yeates

Journal of the Department of Agriculture, Western Australia, Series 4

The level of acidity of a soil reflects its chemical and sometimes its biological condition. Changes in acidity mean changes in the availability to plants of some soil elements, and modifications to the biological processes in the soil.

Some elements become more available to plants in acis soils, and in some soils particular elements can reach toxic levels. Other elements can be effected in the opposite way: deficiencies can develop in acid conditions.

It is important to realise, however, that the chemical nature of all soils varies. Beccause of these variations, acidity can affect each soil differently and thus influence …

Deformation In A Chiral Bag Model, John W. Hunter

Dissertations, Theses, and Masters Projects

A chiral bag model including the effects of quarks, gluons and pions is calculated perturbatively to second order. The bag shape is determined from the requirement that the pressure exerted by the fields be zero at the bag surface. to second order the nucleon is found to be spherical, while the (DELTA) is oblate or prolate for spin projections (VBAR)m(,z)(VBAR) = 3/2, (VBAR)m(,z)(VBAR) = 1/2 respectively. The coupling constants g(,(pi)(DELTA)(DELTA)) and g(,(pi)NN) are calculated and the ratio g(,(pi)(DELTA)(DELTA))/g(,(pi)NN) is an improvement over previous work. The nucleon and (DELTA) magnetic moments are also calculated.

Acoustic Radiation-Induced Static Strain In Single Crystal Silicon, Ka Kui Peter Li

Dissertations, Theses, and Masters Projects

Quantitative verification of the existence of static acoustic displacements generated by acoustic waves propagating in single crystal samples of intrinsic silicon is presented. Measurements are made of the static displacements generated by 30 MHz acoustic compressional waves propagating along the 111 , 110 , and 100 crystalline directions. From these measurements the nonlinearity parameters are calculated and found to have the value 3.87 along the 111 direction, 4.23 along the 110 direction, and 2.13 along the 100 direction. These results are in agreement with values obtained independently from harmonic generation and pressure derivative measurements. Implications of the present work to …

A Theory Of Associative Detachment, Susan Elizabeth. Haywood

Dissertations, Theses, and Masters Projects

In this thesis a theory of associative detachment (A('-) + B (--->) AB + e) is presented. The theory is based on the close-coupling theory of Wang and Delos, but is more general in that final states of the nuclei (AB) are treated quantum mechanically. This is necessary since the molecule may be in any one of several vibrational states. The Schroedinger equation is reduced to an infinite set of coupled equations using carefully chosen assumptions. The coupled equations are uncoupled and the resulting equation for the wave function of the negative ion is solved to zero and first …

Electron Detachment In Negative Ion-Molecule Collisions, Mohammed Saiful Huq

Dissertations, Theses, and Masters Projects

Absolute total cross sections for electron detachment, reactive scattering, charge transfer and dissociative charge transfer have been measured for collisions of hydrogen and halogen negative ions with various molecular targets. The reactants investigated involve H('-), D('-), F('-), Cl('-), Br('-) and I('-) ions as projectiles and H(,2), D(,2), HD, N(,2), CO, O(,2), CO(,2), CH(,4) and Cl(,2) molecules as targets. The energy range of these experiments extended from about 1 eV to about 300 eV in the lab.;The threshold behavior of the detachment cross sections for the reactants H('-)(D('-)) + H(,2),D(,2) and HD has been determined. The thresholds for detachment for both …

Atlas Of High Resolution Infrared Spectra Of Carbon Dioxide: February 1984 Edition, D. Chris Benner

Arts & Sciences Articles

Long-path, low-pressure laboratory absorption spectra of carbon dioxide i are presented in an atlas format for the spectral regions 1830 to 2100 cm" , 2395 to 2680 cm-I i , and 3140 to 3235 cm- . The data were recorded at 0.01 cm"I resolution and room temperature with the Fourier transform spectrometer in the McMath solar telescope complex of the National Solar Observatory at Kitt Peak. A list of positions and assignments is given for the 3336 lines observed. A total of 52 bands of 12C1602, 13C1602, 12C160180, 12C160170, and 13C160180 have been identified.

Systematic Estimate Of Binding Energies Of Weakly Bound Diatomic Molecules, Linda L. Vahala, Mark D. Havey

Electrical & Computer Engineering Faculty Publications

There is often insufficient spectroscopic data for a full RKR inversion to yield a potential for weakly bound diatomic molecules. In these cases, parametrized functions such as the Morse or Thakkar potentials may be used to obtain estimates of the binding energy. The Thakkar potential is more flexible, and has been used successfully on some weakly bound systems. In the more usual case, the Thakkar parameter p, which determines long range behavior R^-p, is chosen by p=-a₁-1, where a₁ is the first Dunham coefficient; p is usually noninteger. The authors present …

Radiation Damage To Gaas Solar Cells Including Isotropic Effects, Larry Victor Stock

Physics Theses & Dissertations

A model is developed for the short circuit current of a GaAs solar cell due to radiation (proton or electron) induced defects in the crystal structure. This model is verified by a comparison with proton and electron irradiation results. For electron radiation and energetic protons (energy> 10 MeV), it is found that the damage in the crystal is independent of the angle of incidence. On the other hand, for lower energy proton radiation, the damage as a function of cell thickness is highly dependent on incident angle and energy. The cell's response to low energy protons is strongly dependent on …

Possibilities For Finite Grand Unification With N = 2 Supersymmetry, Asim Gangopadhyaya

Asim Gangopadhyaya

Predicting The Proton Mass From Pi-Pi-Scattering Data, Jf Donoghue, E Golowich, Br Holstein

Barry R Holstein

We relate experimental information on ππ scattering to tree-level effective chiral Lagrangians. The result is of a form similar to that used in Skyrme-type models of the proton, where the nucleons are described as topologically stable solitons of the chiral fields. In such models, one can express the proton mass in terms of measured scattering data, with the result Mp=880±300 MeV. We interpret this as a consistency test for the Skyrme models.

Pseudo-Brewster And Second-Brewster Angles Of An Absorbing Substrate Coated By A Transparent Thin Film, R. M.A. Azzam, T F. Thonn

Electrical Engineering Faculty Publications

The pseudo-Brewster angle of minimum reflectance for the p polarization, the corresponding angle for thes polarization, and the second-Brewster angle of minimum ratio of the p and s reflectances are all determined as functions of the thickness of a transparent film coating an absorbing substrate by numerical solution of the exact equations that govern such angles of the form Re(Z′/Z) = 0, where Z = R_p, R_s, or ρ represent the complex amplitude-reflection coefficients for the p and s polarizations and their ratio (ρ =R_p/R_s), …

Magnetic Phase Transition, Aggregate Formation, And Electrical Conductivity In Fecl3-Doped Polyacetylene, E. K. Sichel, M. F. Rubner, J. Georger, Jr., G. C. Papaefthymiou, S. Offer, Richard B. Frankel

Physics

Both Fe³⁺ and Fe²⁺ ions occur in FeCl₃-doped polyacetylene. At low dopant levels (2+ and Fe³⁺ ions are paramagnetic down to 4.2 K. At dopant levels >0.01 mole fraction, there is evidence from Mössbauer spectroscopy that Fe²⁺ ions associate into aggregates which are magnetically ordered below 25 K. Aggregate formation appears to correlate with high electrical conductivity.