Results 181 to 190 of about 22,029 (223)
Some of the next articles are maybe not open access.
The dynamic ionospheric polar hole
Radio Science, 1993At a time when most polar cap ionospheric studies are focused on electron density enhancements caused by patches or arcs, this paper discusses an F region depletion known as the ionospheric polar hole. Statistically, polar holes tend to develop on the nightside from 2100–0600 MLT between 70°–80°Λ.
G. Crowley +5 more
openaire +1 more source
ARCTIC, 1969
Defines the ionsphere and describes its three horizontal layers or regions, distinguished by physical characteristics and ionization processes: as quiet D, E and F regions and as disturbed D, E and F regions when there is a disturbed sun (sunspot magma).
openaire +1 more source
Defines the ionsphere and describes its three horizontal layers or regions, distinguished by physical characteristics and ionization processes: as quiet D, E and F regions and as disturbed D, E and F regions when there is a disturbed sun (sunspot magma).
openaire +1 more source
Ionosphere-induced cross polarization of circularly polarized UHF propagation
IEEE Transactions on Antennas and Propagation, 1991To explore the possibility of more efficient spectrum use in the UHF satellite communication band, ionosphere-induced cross polarization of circularly polarized waves was investigated. The Poincare sphere is used to obtain a simple closed-form expression of cross polarization for propagation at an arbitrary angle with respect to the geomagnetic field ...
T.-S. Chu, H.F. Lenzing
openaire +1 more source
Irregularity motions in the polar ionosphere
Radio Science, 1973The frequency spectrum of a CW HF radio signal transmitted from an aircraft and propagated over a 1‐hop path inside the polar cap was recorded for about 50 nighttime hr during August 1967. Two different general types of disturbance were observed in these records: (a) a diffuse spectral broadening which was always present to some extent, even under ...
Roy P. Basler +2 more
openaire +1 more source
Phase scintillations at the polar ionosphere
2013 IEEE International Conference on Space Science and Communication (IconSpace), 2013A dual-frequency GPS Ionospheric Scintillation and TEC Monitor (GISTM) receiver, GSV4004B, has been installed at Alert, Canada (82.48° N, 297.75° E, corresponding to 86.95° N, 155.77° E geomagnetic coordinate) since May 2008 to study the ionospheric variability at a high-latitude location.
M.J. Homam +2 more
openaire +1 more source
A snapshot of the polar ionosphere
Planetary and Space Science, 1976This paper presents a picture of the north polar F layer and topside ionosphere obtained primarily from three satellites (Alouette 2, ISIS 1, ISIS 2) that passed over the region within a time interval of about 50 min on a magnetically quiet day. The horizontal distribution of electron densities at the peak of the F layer is found to be similar to ...
J.H. Whitteker +5 more
openaire +1 more source
Polar, Magnetic, Auroral, and Ionospheric Phenomena
Reviews of Modern Physics, 1960storms which appear to arise from atmospheric sources, though their ultimate causes may be situated beyond the atmosphere. The intense electric currents flowing in the auroral regions are described with related spacial features of the polar and low latitude fields measurable by polar orbiting earth satellites. The earth as a mirror machine is described,
openaire +1 more source
Light ion velocities in the polar ionosphere
Journal of Geophysical Research: Space Physics, 1981High‐speed flow of light ions along magnetic field lines is not simply a consequence of those field lines having an open topology. Here we point out that the magnitude of the H+ flow velocity in the polar wind is not predicted by theoretical models but rather it is imposed as a boundary condition.
J. A. Murphy, R. A. Heelis
openaire +1 more source
POLARIZATION OF IONOSPHERICALLY PROPAGATED WAVES
1967Abstract : The theory of wave propagation in the ionosphere, supported by experimental measurements, is used to demonstrate that regular amplitude variations in HF sweep-frequency oblique-ionogram one-hop rays - when linearly polarized receiving antennas are employed - are due to corresponding variations of the received wave polarization with radio ...
openaire +1 more source
Electromagnetic resonances in the polar ionosphere
Space Science Reviews, 1980The utilization of resonant oscillations for ionospheric modification experiments and ionospheric diagnosis, based on plasma physics and non-linear electrodynamics, is discussed. The spectra of resonant oscillations of natural and artificial origin in the polar ionosphere and the excitation of these oscillations and their development are analysed.
openaire +1 more source