Results 191 to 200 of about 4,774 (237)

Ion velocity distributions in the auroral ionosphere

Planetary and Space Science, 1972
Abstract For application to studies of the auroral ionosphere we have calculated the velocity distribution of the ions in a weakly-ionized plasma subjected to crossed electric and magnetic fields. We have retained enough terms in the series expansion of the distribution to enable us to determine under what conditions departures from the Maxwellian ...
Robert W. Schunk, James C.G. Walker
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The temperature of the ionosphere in the auroral zone

1959
In the absence of man-made interference and atmospherics, it has been found possible to measure radio frequency thermal radiation from the ionosphere at medium frequencies. The temperature of the ionospheric D-region has been previously measured by this method at 2 Mc/s in temperate latitudes (Pawsey, McCreddy and Gardner, 1951, and Gardner, 1954).
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Energy Input to the Auroral Ionosphere.

1980
Abstract : This effort was to aid studies of the high latitude ionosphere particularly with regard to Joule heating processes. For energy input to the atmosphere by Joule heating the dominant physical factor has been found to be the strength of the electric field - the motions of the ionospheric plasma through the nearly stationary neutral gas.
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Auroral infrasonic and ionospheric absorption substorms

Journal of Atmospheric and Terrestrial Physics, 1970
Abstract The median global pattern for the progression of auroral absorption onsets is compared with the distribution of auroral infrasonic waves along the auroral oval. There is agreement between the directions of auroral motions as determined on one hand by the pattern of absorption onsets and on the other hand by the infrasonic wave morphology ...
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Time lags in the auroral zone ionosphere

Planetary and Space Science, 1971
Abstract Fast response riometers were operated at Macquarie Island (invariant latitude 64°S) in conjunction with balloon-borne X-ray scintillators, a λ4278 A photometer, and a loop for detecting micropulsations. The pulsations in cosmic noise absorption (CNA) observed with the riometers were found to lag behind pulsations in bremmstrahlung X-rays ...
J.S. Reid, J. Phillips
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The shape of ionospheric irregularities in the auroral zone

Canadian Journal of Physics, 1987
The evidence that ionospheric irregularities are elongated along the magnetic field is overwhelming. The actual extent of the elongation may, at least for mid-latitude locations, be considerably more than is usually quoted. Several years ago it was suggested that ionospheric irregularities, particularly at night in the auroral zone, are also elongated
G. F. Lyon, J. Davies, P. A. Forsyth
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A numerical simulation of auroral ionospheric electrodynamics

Journal of Geophysical Research: Space Physics, 1985
A computer simulation of auroral ionospheric electrodynamics in the altitude range 80 to 250 km has been developed. The routine will either simulate typical electron precipitation profiles or accept observed data. Using a model background ionosphere, ion production rates are calculated from which equilibrium electron densities and the Hall and Pedersen
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Upflowing ionospheric ions in the auroral region

Journal of Geophysical Research: Space Physics, 1992
Observations of upflowing ionospheric ions are obtained nearly simultaneously by DE 1 and DE 2 over the nightside auroral regions. At low altitudes, the mean value of the net upward ion number flux is of the order of 109 cm−2 s−1. The ionosphere is predominantly O+, and the flux of ions with energy greater than 5 eV is a very small fraction (less than ...
G. Lu, P. H. Reiff, T. E. Moore, R. A. Heelis   +3 more
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Basic concepts in the electrodynamics of the auroral ionosphere

Astrophysics and Space Science, 1982
Equations governing the large-scale electrodynamic processes in the auroral ionosphere are systematically discussed and the limits to drawing conclusions from incomplete sets of equations are evaluated. The vectors of electic current density,j, and electric field,E, are expressed as explicit functions of the densities, pressures and velocities of the ...
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The heights of ionospheric irregularities in the auroral zone

Journal of Geophysical Research, 1962
Recordings of the 20 Mc/s signal strength of the satellite 1958 delta 2 were made. A spaced-receiver technique for measuring the heights of the irregularities responsible for the violent scintillations observed in these signals gives evidence that their altitudes ranged as high as 1000 km.
Roy P. Basler, Ronald N. DeWitt
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