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Equatorial Disturbance Dynamo Electric Fields, Bela G. Fejer, M. F. Larsen, D. T. Farley
Equatorial Disturbance Dynamo Electric Fields, Bela G. Fejer, M. F. Larsen, D. T. Farley
Bela G. Fejer
F-region vertical drift data from Jicamarca, Peru show that equatorial east-west electric fields are sometimes perturbed 16-24 hours after the onset of geomagnetic storms. These disturbance dynamo electric fields, which must be caused primarily by the action of neutral winds at low and middle latitudes, decrease and sometimes even reverse the quiet time electric field pattern during both daytime and nighttime. The long delay excludes the possibility that gravity waves are responsible and suggests that the thermospheric circulation is disturbed. The data also show that after some storms there are no such delayed disturbances, a fact which may be due …
Studies Of Self-Focusing Instability At Arecibo, D. T. Farley, C. Lahoz, Bela G. Fejer
Studies Of Self-Focusing Instability At Arecibo, D. T. Farley, C. Lahoz, Bela G. Fejer
Bela G. Fejer
Precisely simultaneous radar and satellite measurements at the altitude of reflection of a strong HF heating wave above the Arecibo Observatory were made on June 7, 1977. Parametric instabilities produce strong enhancements in the plasma line and ion line incoherent scatter radar echoes. These echoes also exhibit periodic deep fading that is attributed to a self-focusing instability. This explanation was confirmed by the in situ observation of electron density fluctuations with peak-to-peak amplitudes reaching at least 3% and a spatial dependence that corresponded closely to the radar fading pattern, at least for irregularity wavelengths ranging from a few hundred meters …
First Vhf Auroral Radarinterferometer Observations, J. Providakes, W. E. Swartz, D. T. Farley, Bela G. Fejer
First Vhf Auroral Radarinterferometer Observations, J. Providakes, W. E. Swartz, D. T. Farley, Bela G. Fejer
Bela G. Fejer
The radar interferometer technique first used at the magnetic equator in Peru is also a very powerful means for studying auroral plasma instabilities. We present here the first results, obtained with a 49.92 MHz, 20-25 KW peak power pulsed radar located in Ithaca, NY (42.5° N, 76.4° W). Strong auroral echoes were obtained during several highly active periods. Phase differences between the signals received on the two antennas accurately determine the E-W position, within the scattering volume, of localized scattering centers, and changes in this phase determine the corresponding velocity. The signal Doppler shift describes radial (essentially N-S) motion. The …