This dissertation is a study of rocket induced infrasonic waves that propagate vertically in the thermosphere. Observations of plasma displacements, changes in radio wave propagation direction and changes in received signal strength are made with a vertical incidence high frequency ionospheric radar. The primary objectives of this research is to understand the speed at which the infrasonic waves propagate, how the atmosphere behaves in the presence of infrasonic waves and how radio propagation is effected by infrasonic waves.
Rocket-induced infrasonic waves can be reliably detected in the lower thermosphere, they propagate near the adiabatic speed of sound in the lower atmosphere and accelerate rapidly as they approach the altitude of peak plasma density in the ionosphere. These infrasonic waves are observed to reduce radio wave absorption in the D-region of the ionosphere, modulate the radio wave propagation path when they are near the E-region peak, and modulate both the radio wave propagation path and absorption when they are in the F-region. In the F-region they are also found to cause geomagnetic pulsations in the form of shear Alfven waves, and cause range variations in ionosonde echoes which can result in ionogram deformations. These findings significantly advance understanding of waves in the thermosphere.
|Advisor:||Randall, Cora, Bullett, Terence|
|School:||University of Colorado at Boulder|
|Department:||Atmospheric and Oceanic Sciences|
|School Location:||United States -- Colorado|
|Source:||DAI-B 81/7(E), Dissertation Abstracts International|
|Subjects:||Atmospheric sciences, Meteorology, Plasma physics|
|Keywords:||Atmospheric wave, Hazards, Infrasonic wave, Ionosonde, Space weather|
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