Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 2 of 2
Full-Text Articles in Physics
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 …
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 …