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Articles 1 - 14 of 14
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Auroral E-Region Plasma Waves Andelevated Electron Temperatures, Bela G. Fejer, J. Providakes, D. T. Farley, W. E. Swartz
Auroral E-Region Plasma Waves Andelevated Electron Temperatures, Bela G. Fejer, J. Providakes, D. T. Farley, W. E. Swartz
Bela G. Fejer
We have observed 3-m auroral E region plasma waves with a high-resolution 50-MHz radar interferometer at Ithaca. During postmidnight periods of very strong magnetic activity at Ottawa (L = 3.5), the backscattered power and Doppler spectra vary rapidly with time and range and may have both mean Doppler shifts and half power widths in excess of 200 Hz (600 m/s). In addition, when the radar and magnetometer data imply that the current is approximately parallel to the radar line of sight, sharp spectral peaks corresponding to phase velocities approaching 1 km/s sometimes appear suddenly. These persist for at most several …
Rigid Backbone: A New Geometry For Percolation, Anthony Roy Day, R. R. Tremblay, A.-M. S. Tremblay
Rigid Backbone: A New Geometry For Percolation, Anthony Roy Day, R. R. Tremblay, A.-M. S. Tremblay
Anthony Roy Day
It is shown that the diluted two-dimensional central-force problem belongs to a new class of percolation problems. Geometric properties such as the fractal dimension of the backbone, the correlation-length exponent, and the connectivity are completely different from those of previously studied percolation problems. Explicit calculations of the backbone and the construction of an algorithm which identifies the infinite rigid cluster clearly demonstrate the absence of singly connected bonds, the overwhelming importance of loops, and the long-range nature of the rigidity.
Cooling By Immersion In Liquid Nitrogen, Thomas W. Listerman, Thomas A. Boshinski, Lynn F. Knese
Cooling By Immersion In Liquid Nitrogen, Thomas W. Listerman, Thomas A. Boshinski, Lynn F. Knese
Thomas Listerman
When an object is cooled by immersion in a liquid, there is an unexpected increase in the violence of boiling just before the boiling stops. Most people seem fascinated by this phenomenon yet few are acquainted with its explanation in terms of a change in the heat‐transfer mechanism from film boiling to nucleate boiling. We have developed two variations of an intermediate level undergraduate laboratory experiment to measure the heat‐transfer rate after a sample is immersed in liquid nitrogen. The temperature of the sample, as measured by a thermocouple, is recorded as a function of time using either a potentiometer …
Ferromagnetism Versus Antiferromagnetism In Face-Centered-Cubic Iron, F. J. Pinski, J. Staunton, B. L. Gyorffy, Duane D. Johnson, G. M. Stocks
Ferromagnetism Versus Antiferromagnetism In Face-Centered-Cubic Iron, F. J. Pinski, J. Staunton, B. L. Gyorffy, Duane D. Johnson, G. M. Stocks
Duane D. Johnson
Using a first-principles disordered-local-moment picture of itinerant-electron magnetism, we calculated the temperature and volume dependence of the magnetic moment and spin-spin correlations for fcc Fe in the paramagnetic state.
Density-Functional Theory For Random Alloys: Total Energy Within The Coherent-Potential Approximation, Duane D. Johnson, D. M. Nicholson, F. J. Pinski, B. L. Gyorffy, G. M. Stocks
Density-Functional Theory For Random Alloys: Total Energy Within The Coherent-Potential Approximation, Duane D. Johnson, D. M. Nicholson, F. J. Pinski, B. L. Gyorffy, G. M. Stocks
Duane D. Johnson
A density-functional-based theory is developed for calculation of the total energy and pressure of random substitutional alloys within the Korringa-Kohn-Rostoker coherent-potential approximation. The theory is used to calculate the concentration variation of the equilibrium lattice spacing of α-phase CucZn1−c alloys. We find, in agreement with experiment, that the variation is almost linear and that it deviates from Vegard's rule.
The Condorequatorial Spread-F Campaign: Overview And Results Of The Large-Scale Measurements, M. C. Kelley, J. Labelle, E. Kudeki, Bela G. Fejer, S. Basu, Su. Basu, K. D. Baker, C. Hanuise, P. Argo, R. F. Woodland, W. E. Swartz, D. T. Farley, J. W. Meriwether
The Condorequatorial Spread-F Campaign: Overview And Results Of The Large-Scale Measurements, M. C. Kelley, J. Labelle, E. Kudeki, Bela G. Fejer, S. Basu, Su. Basu, K. D. Baker, C. Hanuise, P. Argo, R. F. Woodland, W. E. Swartz, D. T. Farley, J. W. Meriwether
Bela G. Fejer
During the Condor campaign a number of instruments were set up in Peru to support the rocket experiments. In this series of papers we report on the results of the experiments designed to study the equatorial F region. In this overview paper we summarize the main results as well as report upon the macroscopic developments of spread F as evidenced by data from backscatter radars, from scintillation observations, and from digital ionosonde meaurements. In this latter regard, we argue here that at least two factors other than the classical gravitational Rayleigh-Taylor plasma instability process must operate to yield the longest-scale …
Gigahertz Scintillations And Spaced Receiver Drift Measurements During Project Condorequatorial F-Region Rocket Campaign In Peru, S. Basu, Sa. Basu, J. Labelle, E. Kudeki, Bela G. Fejer, M. C. Kelley, H. E. Whitney
Gigahertz Scintillations And Spaced Receiver Drift Measurements During Project Condorequatorial F-Region Rocket Campaign In Peru, S. Basu, Sa. Basu, J. Labelle, E. Kudeki, Bela G. Fejer, M. C. Kelley, H. E. Whitney
Bela G. Fejer
Radar backscatter at 50 MHz, rocket, and VHF/GHz scintillation measurements of spread F irregularities at the magnetic equator in Peru were made during the Project Condor campaign in March 1983. The paper discusses the coordinated set of observations on two evenings, March 1 and March 14, 1983, when the altitude of the F region peak differed by more than 150 km. The full complement of equatorial spread F phenomena, namely, the occurrence of 3-m plume structures and VHF/GHz scintillations, were recorded on both these evenings. It was found that the radar backscatter with extended plumes occurs in association with maximum …
On The Quadratic Form N12 +N22 +N32 - N42 In Z4, Andrei Ludu
On The Quadratic Form N12 +N22 +N32 - N42 In Z4, Andrei Ludu
Andrei Ludu
No abstract provided.
Measurements Of Electron Energy Distribution In An Argon Positive Column, Chin Oi Hoong
Measurements Of Electron Energy Distribution In An Argon Positive Column, Chin Oi Hoong
Chin Oi Hoong
The argon positive column plasma of a cold cathode glow discharge is studied using a pulsed single Langmuir Probe technique. It is observed thatthe energy distribution of the electrons in the posotive column is non-maxwellian at a gas pressure of 0.5 mbar. An increase in the gas pressure seems to make the distribution more Maxwellian.
The Prereversal Enhancement Of Thezonal Electric Field In The Equatorial Ionosphere, D. T. Farley, E. Bonelli, Bela G. Fejer, M. F. Larsen
The Prereversal Enhancement Of Thezonal Electric Field In The Equatorial Ionosphere, D. T. Farley, E. Bonelli, Bela G. Fejer, M. F. Larsen
Bela G. Fejer
The electric fields in the ionospheric E and F regions near the magnetic equator often show a strong eastward enhancement shortly after sunset and before the eastward (normally) daytime field reverses to westward. Several theoretical models of the low-latitude fields suggest that this enhancement is caused mainly or entirely by F region winds (the F region dynamo), but some authors have suggested that it could be produced solely by E region tidal winds. We give here additional calculations and arguments in support of the F region source. The enhancement of the eastward field for an eastward F region wind turns …
Renormalization-Group Analysis Of Heat Capacity Amplitude, Scott I. Chase, Miron Kaufman
Renormalization-Group Analysis Of Heat Capacity Amplitude, Scott I. Chase, Miron Kaufman
Miron Kaufman
Critical amplitudes A+ associated with the temperature variation of the heat capacity are analyzed by means of renormalization-group techniques in both position and momentum spaces. We describe a mechanism according to which the amplitudes A diverge as the critical exponent a approaches a nonpositive integer. In between two consecutive divergences at least one amplitude vanishes at least once. The coefficient P in the expansion A+ /A- =1—Pa+0 (a~) is computed by means of e expansion and Migdal-Kadanoff renormalization-group technique. Systems for which the critical exponent alpha is negative but larger than —1 exhibit either a cusped heat capacity if A+/A- …
Nonequilibrium Fluctuations Studied By A Rarefied Gas Simulation, Alejandro Garcia
Nonequilibrium Fluctuations Studied By A Rarefied Gas Simulation, Alejandro Garcia
Alejandro Garcia
A dilute gas under a constant heat flux is studied with use of a Monte Carlo simulation based on the Boltzmann equation. Results for several spatial correlation functions of equal-time fluctuations are reported and compared qualitatively with previous fluctuating hydrodynamics calculations for liquids.
The Rigid Backbone: A New Geometry For Percolation., Anthony Day, R. Tremblay, A.-M. Tremblay
The Rigid Backbone: A New Geometry For Percolation., Anthony Day, R. Tremblay, A.-M. Tremblay
Anthony Roy Day
It is shown that the diluted two-dimensional central-force problem belongs to a new class of percolation problems. Geometric properties such as the fractal dimension of the backbone, the correlation-length exponent, and the connectivity are completely different from those of previously studied percolation problems. Explicit calculations of the backbone and the construction of an algorithm which identifies the infinite rigid cluster clearly demonstrate the absence of singly connected bonds, the overwhelming importance of loops, and the long-range nature of the rigidity.
Splay Rigidity In The Diluted Central Force Elastic Network, Anthony Roy Day, A.-M. S. Tremblay, R. R. Tremblay
Splay Rigidity In The Diluted Central Force Elastic Network, Anthony Roy Day, A.-M. S. Tremblay, R. R. Tremblay
Anthony Roy Day
A Comment on the Letter by Wang and Harris, Phys. Rev. Lett. 55, 2459 (1985).