The role of acoustic-gravity waves in generating equatorial ionospheric irregularities
Abstract
The spatial resonance amplification of traveling ionospheric disturbance (TIDs) generated by acoustic gravity waves was studied. As the wave profile in the plasma steepens, the stored energy begins to release through the Rayleigh-Taylor instability, which then creates a spectrum of smaller scale irregularities. The interaction of the acoustic gravity wave and the ionospheric plasma are examined, the interaction between a neutral wave and the plasma is quantified, and the conditions for growth of resonant plasma waves are established. These conditions are met during the post-sunset period near the geomagnetic equator which is exactly when and where the irregularities are encountered. For irregularity generation, the Rayleigh-Taylor mechanism requires a steep positive gradient of density, a fact that previously has seemed to be impossible on the topside of the F-layer. It is shown that acoustic gravity waves can generate positive slopes even on the topside F-layer. Consequently, acoustic gravity waves constitute a single mechanism that can be used to explain both bottomside and topside irregularities.
- Publication:
-
Ph.D. Thesis
- Pub Date:
- March 1980
- Bibcode:
- 1980PhDT........25A
- Keywords:
-
- Equatorial Atmosphere;
- F Region;
- Gravity Waves;
- Ionospheric Disturbances;
- Magnetic Equator;
- Plasma Waves;
- Density Distribution;
- Resonance;
- Taylor Instability;
- Transequatorial Propagation;
- Geophysics