EFFECT OF PLASMA INSTABILITIES ON THE CREATION OF METEOR TRAIL ECHOES
Open Access
- Author:
- Galindo Palomino, Freddy Ronald
- Graduate Program:
- Electrical Engineering
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- July 09, 2018
- Committee Members:
- Julio Urbina, Dissertation Advisor/Co-Advisor
Julio Urbina, Committee Chair/Co-Chair
John Mathews, Committee Member
James Kenneth Breakall, Committee Member
David Bradley Spencer, Outside Member - Keywords:
- Radar Remote Sensing
Meteors
Plasma Instabilities - Abstract:
- Everyday millions of meteoroids smaller than a grain of sand enter the Earth’s upper atmosphere and generate meteor plasma trails at altitudes between 70 and 140 km. These meteor trails present a powerful opportunity to use remote sensing tools to better understand the meteoroids that produced them and the background atmosphere in which these trails occur. In this regard, radars are one of most promising tools because these instruments can routinely observe distinct types of meteor trail echoes. This dissertation investigates the impact that plasma instabilities developing in the trail itself exert on the creation of both non-specular and underdense specular meteor trail echoes. The investigation is performed using numerical models to simulate non-specular and underdense specular meteor trail echoes. These models are based on meteor physics that track the evolution of an individual meteoroid from atmospheric entry to trail instability and diffusion. The theoretical results demonstrate that: a) meteor plasma instabilities can develop between 84 km and 107 km altitude, b) neutral winds play an important role on the signal pattern of non-specular meteor echoes, c) meteor diffusion values extracted from underdense meteor trail echoes exhibit an intrinsic bias due to the deposition of meteoric material, d) underdense specular trail echoes could exhibit a double decay signature due to plasma instabilities, e) plasma instabilities could affect meteor fluxes computed from underdense metero echoes, among other findings. The theoretical findings are corroborated by comparing them against observational meteor data. Non-specular meteor investigations employ data collected during the COQUI-II campaign and Eta-Aquariids meteor shower campaign. Specular meteor analyses use meteor data collected with the Illinois SKiYMET radar (latitude 40.17º N, longitude 88.16º W). Finally, I provide possible directions for future work in meteor trail echoes.