Radar-based analysis approach for the characterization of plasma turbulence in the ionosphere

Abstract

Understanding the space environment, through the study of earth's ionosphere, is essential for understanding and designing today's complex communication systems. This thesis focuses on utilizing recent advances in signal processing towards the characterization of ionospheric plasma turbulence. Previous theoretical work, by Kuo and Lee, predicts that plasma turbulence induced by the parametric decay instability propagates downward once it is excited. Unfortunately, due to limitations in altitude resolution on available radar systems, previous experimental work produced only limited evidence supporting this theory. My thesis focuses on proving Kuo and Lee's theory through utilizing quadric time-frequency distributions, specifically the Wigner-Ville Distribution. This analysis approach allows one to analyze the backscattered energy as a function of time at an inter-pulse level. The resulting fine time resolution allows me to observe the flow of energy between the coarse altitude bins and subsequently infer the propagation direction of the instability. Using this Energy-Flow Analysis technique on experimental data collected in Alaska on August 6 - 9, 2012, I observed downward propagating turbulence that further substantiates the theory by Kuo and Lee.