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High Latitude Plasma Convection: Predictions For Eiscat And Sondre Stromfjord, Jan Josef Sojka, W. John Raitt, Robert W. Schunk Jan 1979

High Latitude Plasma Convection: Predictions For Eiscat And Sondre Stromfjord, Jan Josef Sojka, W. John Raitt, Robert W. Schunk

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We have used a plasma convection model to predict diurnal patterns of horizontal drift velocities in the vicinity of the EISCAT incoherent scatter facility at Tromso, Norway and for Sondre Stromfjord, Greenland, a proposed new incoherent scatter facility site. The convection model includes the offset of 11.4° between the geographic and geomagnetic poles (northern hemisphere), the tendency of plasma to corotate about the geographic pole, and a magnetospheric electric field mapped to a circle about a center offset by 5° in the antisunward direction from the magnetic pole. Four different magnetospheric electric field configurations were considered, including a constant cross‐ …

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Effect Of Displaced Geomagnetic And Geographic Poles On High-Latitude Plasma Convection And Ionospheric Depletions, Jan Josef Sojka, W. J. Raitt, Robert W. Schunk Jan 1979

Effect Of Displaced Geomagnetic And Geographic Poles On High-Latitude Plasma Convection And Ionospheric Depletions, Jan Josef Sojka, W. J. Raitt, Robert W. Schunk

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We assumed that the ionospheric plasma at high latitudes has a tendency to corotate about the geographic pole and that magnetospheric convection is relative to the geomagnetic pole. With this assumption we calculated plasma drift patterns over the polar cap for a range of constant magnetospheric electric fields as well as for asymmetric electric fields with enhanced plasma flow on either the dawnside or the duskside of the polar cap. We calculated the drift patterns in both the geographic inertial and the geomagnetic inertial frame taking into account the displacement between the geographic and geomagnetic poles. We found that this …

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Time Lag In Diffusion-Controlled Nucleation, David Peak Jan 1978

Time Lag In Diffusion-Controlled Nucleation, David Peak

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Nucleation occurring in the presence of a dense solvent is accompanied by spatial correlations among the reactant clusters and monomers which affect the aggregation rates. The classical theory of nucleation, which does not take such correlations into account, overestimates the observed nucleation rate and underestimates the time lag in condensed systems. An explicit expression for the time lag in diffusion‐controlled nucleation is derived. Values associated with miscibility gap experiments differ from the classical predictions by factors of 5 to 10.

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Photoelectron Flux Build-Up In The Plasmasphere, G P. Mantas, Herbert C. Carlson, Vincent B. Wickwar Jan 1978

Photoelectron Flux Build-Up In The Plasmasphere, G P. Mantas, Herbert C. Carlson, Vincent B. Wickwar

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Processes which confine photoelectrons to the plasmasphere (e.g., collisional backscattering from the thermosphere and magnetic trapping due to pitch angle redistribution through Coulomb collisions in the plasmasphere) tend to increase the steady state photoelectron flux in the plasmasphere above the amplitude level that would otherwise have been attained. Theoretical calculations are presented of steady state photoelectron fluxes in the plasmasphere, for specified atmospheric and ionospheric conditions. (Observational plasma line intensity data for these conditions exist and will be compared elsewhere.) General features of the angular distribution are presented and compared with observations. The transparency of the plasmasphere and the backscattering …

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Plasma Lines In The Auroral E Layer, Vincent B. Wickwar Jan 1978

Plasma Lines In The Auroral E Layer, Vincent B. Wickwar

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The first successful measurements of plasma lines in the auroral E layer were made in January 1976 using the Chatanika incoherent scatter radar. Although they are considerably weaker than the signal from the ion component, the plasma line signals are readily detectable. Typical signal-to-noise ratios were about 4%. In this series of experiments, plasma lines were observed in the interval between 3.8 and 6.0 MHz, which corresponds to phase energies between 0.55 and 1.4 eV. They were found between 98 and 134 km; the derived plasma wave intensities varied between 0.06 and 1.0 eV, and the enhancements between 4 and …

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Electron And Ion Temperatures—A Comparison Of Ground-Based Incoherent Scatter And Ae-C Satellite Measurements, R F. Benson, P Bauer, L H. Brace, Herbert C. Carlson, J Hagen, W B. Hanson, W R. Hoegy, M R. Torr, R H. Wand, Vincent B. Wickwar Jan 1977

Electron And Ion Temperatures—A Comparison Of Ground-Based Incoherent Scatter And Ae-C Satellite Measurements, R F. Benson, P Bauer, L H. Brace, Herbert C. Carlson, J Hagen, W B. Hanson, W R. Hoegy, M R. Torr, R H. Wand, Vincent B. Wickwar

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The Atmosphere Explorer-C satellite (AE-C) is uniquely suited for correlative studies with ground-based stations because its on-board propulsion system enables a desired ground station overflight condition to be maintained for a period of several weeks. It also provides the first low-altitude (below 260 km) comparison of satellite and incoherent scatter electron and ion temperatures. More than 40 comparisons of remote and in situ measurements were made by using data from AE-C and four incoherent scatter stations (Arecibo, Chatanika, Millstone Hill, and St. Santin). The results indicate very good agreement between satellite and ground measurements of the ion temperature, the average …

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The Plasma Line Revisited As An Aeronomical Diagnostic: Suprathermal Electrons, Solar Euv, Electron‐Gas Thermal Balance, Herbert C. Carlson, Vincent B. Wickwar, G P. Mantas Jan 1977

The Plasma Line Revisited As An Aeronomical Diagnostic: Suprathermal Electrons, Solar Euv, Electron‐Gas Thermal Balance, Herbert C. Carlson, Vincent B. Wickwar, G P. Mantas

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Spectra of plasma wave intensities (kTp) in the ionosphere over Arecibo are calculated and compared with those from observations of the plasma line intensity. This approach involving directly observed quantities avoids the uncertainties that have plagued past comparisons with photoelectron theory. In addition, careful comparisons in physically relevant segments of the spectra show that any significant increase in the magnitude of the solar EUV flux would lead to a contradiction of the observed plasma wave intensities. Further, the comparisons indicate that resolution of the thermal electron‐gas heat balance problem must be sought through better heat transfer rates (e.g., …

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Competitive Effect On The Rate Of The Diffusion-Controlled Reaction A+B→C, David Peak, K Pearlman, P J. Wantuck Jan 1976

Competitive Effect On The Rate Of The Diffusion-Controlled Reaction A+B→C, David Peak, K Pearlman, P J. Wantuck

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None available; appears in letters section.

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Ionization Enhanced Diffusion, David Peak, J W. Corbett, J Bourgoin Jan 1976

Ionization Enhanced Diffusion, David Peak, J W. Corbett, J Bourgoin

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The general three‐dimensional diffusion equations, along with the corresponding tensor diffusivities, are established for the normal ionization‐enhanced diffusion mechanism (which is equivalent to a general two‐channel diffusion mechanism) and for the Bourgoin mechanism, the latter being explicitly developed for the diamond lattice.

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Impurity-Concentration Profile For An Exponentially Decaying Diffusion Coefficient In Irradiation Enhanced Diffusion, J Kowall, David Peak, J W. Corbett Jan 1976

Impurity-Concentration Profile For An Exponentially Decaying Diffusion Coefficient In Irradiation Enhanced Diffusion, J Kowall, David Peak, J W. Corbett

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The diffusion equation is solved for a semi-infinite region in the case of irradiation-enhanced diffusion produced by a diffusion coefficient falling off exponentially in the medium. Near the surface the concentration profile due to enhanced diffusion has a larger concentration than the profile due to thermal diffusion; conversely far from the surface the enhanced-diffusion profile has a lower concentration than that due to thermal diffusion. Thus, this type of enhanced diffusion results in a more abruptly changing profile than does thermal diffusion.

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Auroral Energy Input From Energetic Electrons And Joule Heating At Chatanika, Vincent B. Wickwar, M J. Baron, R D. Sears Jan 1975

Auroral Energy Input From Energetic Electrons And Joule Heating At Chatanika, Vincent B. Wickwar, M J. Baron, R D. Sears

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With the incoherent scatter radar at Chatanika, Alaska, a wide variety of measurements can be made related to the ionosphere, magnetosphere, and neutral atmosphere. A significant parameter is the amount of energy transferred from the magnetosphere into the ionosphere and neutral atmosphere during periods of auroral activity. In this report we examine a procedure whereby the incident energy flux of auroral electrons is ascertained from radar measurements. As part of the process we compare radar-determined fluxes with those ascertained from simultaneous photometric observations at 4278 Å. The fluxes obtained by both techniques had similar magnitudes and time variations. If we …

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Incoherent Scatter Radar Observations Of Westward Electric Fields And Plasma Densities In The Auroral Ionosphere, 1, M P. Banks, C L. Rino, Vincent B. Wickwar Jan 1974

Incoherent Scatter Radar Observations Of Westward Electric Fields And Plasma Densities In The Auroral Ionosphere, 1, M P. Banks, C L. Rino, Vincent B. Wickwar

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This paper reports the results of incoherent scatter radar observations of high-altitude ion drifts and other plasma parameters made February 24, 1972, at Chatanika, Alaska (L = 5.7), during a period of magnetic disturbance. For this experiment, conducted between 0909 to 1303 UT (2309 to 0303 AST), the radar line of sight was held fixed in the magnetic meridian plane so that the observed north-south ion drifts could be interpreted in terms of a westward electric field that ranged in magnitude from −10 to +35 mV m−1. The results confirm many effects found previously through other experimental …

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Combined Airglow And Incoherent Scatter Observations As A Technique For Studying Neutral Atmospheric Variations, L L. Cogger, Vincent B. Wickwar, Herbert C. Carlson Jan 1974

Combined Airglow And Incoherent Scatter Observations As A Technique For Studying Neutral Atmospheric Variations, L L. Cogger, Vincent B. Wickwar, Herbert C. Carlson

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Night airglow 6300 Å intensities and electron density altitude profiles observed at Arecibo have been combined with dissociative recombination theory to obtain information about the nighttime variation of F-region N2 and O2 densities. The application of this technique is illustrated using data from two nights in March 1971. The gross nighttime variation shows reasonable similarity to the Jacchia [1970] model, and also follows the time variation of the measured exospheric temperature. However, on both nights there is evidence of a postmidnight enhancement of the O2/N2 density ratio associated with a rapid decrease in the …

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Incoherent-Scatter Radar Observations Of Westward Electric Fields, 2, C L. Rino, Vincent B. Wickwar, P M. Banks, E Rieger, S Akasofu Jan 1974

Incoherent-Scatter Radar Observations Of Westward Electric Fields, 2, C L. Rino, Vincent B. Wickwar, P M. Banks, E Rieger, S Akasofu

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In this paper we describe the results of a series of geomagnetic meridian plane radar incoherent scatter plasma transport measurements. From such data the eastward (zonal) component of the electric field can be deduced. The results show that the electric field has an eastward component whenever the discrete auroras are northward of the region of the measurement. The zonal field component turns westward as the discrete auroras move equatorward of the region of the measurement. Thus there is an eastward electric field boundary near the equatorward limit of the discrete aurora, which is the poleward boundary of the diffuse aurora …

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Carbon Interstitial In The Diamond Lattice, C Weigel, David Peak, J W. Corbett, R P. Messmer, G D. Watkins Jan 1973

Carbon Interstitial In The Diamond Lattice, C Weigel, David Peak, J W. Corbett, R P. Messmer, G D. Watkins

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Linear-combination-of-atomic-orbitals-molecular-orbitals cluster calculations using the extended Hückel theory are carried out for the interstitial carbon in the diamond lattice. The results suggest that the interstitial configuration is not the tetrahedral or hexagonal site, as has been previously assumed, but is instead an "interstitialcy" configuration, i.e., either a split- 〈100〉 interstitial (which our results favor) or a bond-centered interstitial. The predicted minimum-energy configuration changes with charge state, suggesting that the interstitial in the diamond lattice is a possible example of the Bourgoin mechanism of athermal migration of a defect in the presence of ionizing radiation.

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Ionization‐Enhanced Diffusion: Ion Implantation In Semiconductors, J Bourgoin, David Peak, J W. Corbett Jan 1973

Ionization‐Enhanced Diffusion: Ion Implantation In Semiconductors, J Bourgoin, David Peak, J W. Corbett

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A model for the diffusion of implanted interstitials during implantation is introduced and shown to be able to account for the tails observed in ion profiles. It is argued that mechanisms of ionization‐enhanced diffusion can explain some of the anomalous diffusion mechanisms observed in semiconductors. Indications for the existence of such mechanisms in the field of ion implantation in semiconductors are discussed.

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The Momentum Of The Photon, K F. Ratcliff, David Peak Jul 1972

The Momentum Of The Photon, K F. Ratcliff, David Peak

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No abstract provided.

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Diffusion-Controlled Reaction Kinetics, David Peak, J W. Corbett Jan 1972

Diffusion-Controlled Reaction Kinetics, David Peak, J W. Corbett

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The theory of diffusion-controlled correlated reaction kinetics is developed for the radiation boundary condition (RBC) at the reaction surface. Limited only by the assumptions of purely radial spatial dependence, of a spherical reaction surface, and of continuum diffusion, these results comprise a complete solution for these kinetics. The limiting solutions are obtained for the case of the Smoluchowski boundary condition (SBC) at the reaction surface; numerical solutions are presented, as are the analytic forms of certain limiting cases. The initial recovery for the RBC is linear in time, whereas for the SBC it is well known to be proportional to …

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The 6300Å Predawn Enhancement: Excitation By Protoelectrons From The Magnetic Conjugate Point, Vincent B. Wickwar Jan 1972

The 6300Å Predawn Enhancement: Excitation By Protoelectrons From The Magnetic Conjugate Point, Vincent B. Wickwar

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Incoherent scatter and tilting filter photometer data from Arecibo Observatory were combined to search for a contribution to the 6300 Å predawn enhancement due to impact excitation by photoelectrons from the magnetic conjugate point. Prior to about 105° conjugate solar zenith angle, calculations of the 6300 Å intensities due to dissociative recombination gave good agreement with the observed intensities. Then, with the arrival of conjugate photoelectrons (confirmed by plasma line enhancements), the observed intensities rose above the calculated, the difference increasing until a plateau was achieved at a conjugate solar zenith angle of about 95°. The difference or residual intensity …

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Properties Of The Interstitial In The Diamond-Type Lattice, G D. Watkins, R P. Messmer, C Weigel, David Peak, J W. Corbett Jan 1971

Properties Of The Interstitial In The Diamond-Type Lattice, G D. Watkins, R P. Messmer, C Weigel, David Peak, J W. Corbett

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Linear combination of atomic orbital—molecular orbital cluster calculations using extended Hückel theory suggest that the interstitial carbon atom in diamond prefers an "interstitialcy" configuration. The predicted minimum-energy configuration changes with charge state, providing a possible example of the Bourgoin mechanism for "athermal" migration of the interstitial in the presence of ionizing radiation.

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Interpretation Of A Unified Theory Of Gravitation And Symmetry Breaking, David Peak, A Inomata Nov 1969

Interpretation Of A Unified Theory Of Gravitation And Symmetry Breaking, David Peak, A Inomata

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The formalism of Moen and Moffat is interpreted as a Yang-Mills theory set in a space-time generally endowed with curvature and torsion.

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Summation Over Feynman Histories In Polar Coordinates, David Peak, A Inomata Jan 1969

Summation Over Feynman Histories In Polar Coordinates, David Peak, A Inomata

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Use of polar coordinates is examined in performing summation over all Feynman histories. Several relationships for the Lagrangian path integral and the Hamiltonian path integral are derived in the central‐force problem. Applications are made for a harmonic oscillator, a charged particle in a uniform magnetic field, a particle in an inverse‐square potential, and a rigid rotator. Transformations from Cartesian to polar coordinates in path integrals are rather different from those in ordinary calculus and this complicates evaluation of path integrals in polars. However, it is observed that for systems of central symmetry use of polars is often advantageous over Cartesians.

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