This study will investigate radar techniques and low-latitude ionospheric instability and drift processes using the Jicamarca Radio Observatory in Peru. The studies will focus on the origins of equatorial spread-F, long and short period fluctuations in ionospheric plasma drifts and their implications on the coupling of the low-latitude ionosphere to higher latitudes, generation mechanisms of the equatorial irregularities at 150 km altitude and remote sensing of those echoes, broadband measurements of the absolute scattering cross section of equatorial electrojet and 150 km irregularities, and interferometric imaging of ionospheric plasma irregularity structures. Additional research efforts will be directed toward the analysis, modeling, and development of atmospheric/ionospheric radar remote sensing techniques. ***