Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
- Discipline
- Keyword
-
- Auroral (4)
- Waves (2)
- Cyclotron (1)
- Density (1)
- Direction (1)
-
- Drift (1)
- Dynamic (1)
- E region (1)
- Echoes (1)
- Electric (1)
- Electrojet (1)
- Electron (1)
- Field (1)
- Ion (1)
- Ionosphere (1)
- Measurement (1)
- Natural Variatianl principles (1)
- Plamsa (1)
- Plasma (1)
- Possible (1)
- Power (1)
- Radar (1)
- Related (1)
- Resonant (1)
- Riemannian structures (1)
- Source (1)
- Spectra (1)
- Theory (1)
- Variations (1)
- Velocity (1)
- Publication
Articles 1 - 5 of 5
Full-Text Articles in Physical Sciences and Mathematics
Electric Field And Plasma Density Measurements In The Auroral Electrojet, R. Pfaff, M. C. Kelley, Bela G. Fejer, E. Kudeki, C. W. Carlson, A. Pedersen, B. Hausler
Electric Field And Plasma Density Measurements In The Auroral Electrojet, R. Pfaff, M. C. Kelley, Bela G. Fejer, E. Kudeki, C. W. Carlson, A. Pedersen, B. Hausler
Bela G. Fejer
Intense electrostatic waves in the auroral E region have been detected simultaneously on two payloads launched in a mother-daughter configuration from Kiruna, Sweden. The data sets comprise electric field and density measurements from the ambient (dc) conditions to fluctuations as high as 50 kHz. The dc electric field measured by both payloads was 54 mV/m northwest, which corresponded to an electron drift velocity of 1080 m/s. This electric field drove two-stream waves perpendicular to both B and E observed by both spacecraft throughout an altitude region which agrees quite well with the range predicted by linear two-stream theory. The power …
Ion Cyclotron Waves As Apossible Source Of Resonant Auroral Radar Echoes, Bela G. Fejer, R. W. Reed, D. T. Farley, W. E. Swartz, M. C. Kelley
Ion Cyclotron Waves As Apossible Source Of Resonant Auroral Radar Echoes, Bela G. Fejer, R. W. Reed, D. T. Farley, W. E. Swartz, M. C. Kelley
Bela G. Fejer
Auroral backscatter radar observations were made from Ithaca, New York, at 50 MHz during the early morning of April 1, 1976, a period of high magnetic disturbance (Kp ∼ 8). The backscattered power showed large rapid (time scale of a few minutes or less) variations, characteristic of discrete radar aurora, from L = 3.5–4. Doppler spectra of waves propagating in nearly the north-south direction from up to 28 different ranges were obtained simultaneously with good spatial (7.5 km) and temporal (2 s) resolution. Some unusual spectra with very narrow peaks at Doppler shifts between about 70 and 90 Hz were …
Directional And Dynamic Variations Ofauroral Power Spectra Related To The Ionospheric Electron Drift Velocity, E. Nielsen, C. I. Haldoupis, Bela G. Fejer, H. M. Ierkic
Directional And Dynamic Variations Ofauroral Power Spectra Related To The Ionospheric Electron Drift Velocity, E. Nielsen, C. I. Haldoupis, Bela G. Fejer, H. M. Ierkic
Bela G. Fejer
Power spectral observations of auroral electron density fluctuations with a scale length of nearly 1 m have been made with the STARE system (Scandinavian twin auroral radar experiment). Simultaneous measurements of the mean radial Doppler velocities were used to derive estimates of the ionospheric electron drift velocity. The data were analyzed to determine the spectral dependence on the magnitude and direction of the electron drift velocity. The two spectral types, characterized as “narrow” and “broad,” were observed simultaneously from the same scattering volume. The width of the broad spectrum (up to about 1200 Hz) can be at least 3 times …
Theory Of Plasma Waves In The Auroral E-Region, Bela G. Fejer, J. Providakes, D. T. Farley
Theory Of Plasma Waves In The Auroral E-Region, Bela G. Fejer, J. Providakes, D. T. Farley
Bela G. Fejer
We have extended the linear fluid theory of electrojet plasma waves to the region where ion magnetization effects are important. Our general dispersion relation includes the effect of cross-field and field-aligned drifts, ion inertia, electron density gradients, and recombination. In the absence of density gradients and recombinational damping, the oscillation frequency at marginal instability is changed by the ion magnetization effects from the ion acoustic frequency, ω = kCs, to the modified ion cyclotron frequency ω² = Ωi² + k²Cs². These upper E region waves can be driven by field-aligned and/or cross-field drifts and have the smallest threshold drift velocities …
Natural Variational Principles On Riemannian Structures, Ian M. Anderson
Natural Variational Principles On Riemannian Structures, Ian M. Anderson
Ian M. Anderson
No abstract provided.