Coherent backscatter radar imaging of equatorial spread F: Intermediate scale-size structures

Abstract

F-region observations made by a 30 MHz coherent backscatter radar have been used to investigate the morphology of equatorial spread F. Using interferometric radar imaging, two-dimensional inbeam images of scattering structures responsible for ESF echoes have been constructed. The images allow us to resolve the spatial distribution of the scatterers, and to determine, unambiguously, the occurrence of intermediate (a few tens of km) scale-size structures. Here, focus is given to observations made on the night of December 5, 2005. Strong topside and bottomside scattering layers were detected on this night, and well-resolved in-beam images of the scatterers were successfully obtained. Among the imaging results we highlight the detection of narrow, vertically elongated scattering channels spaced by only a few tens of km in the horizontal direction. Such modulation of ESF structures reinforce previous radar imaging results suggesting a possible role of decakilometric plasma waves in ESF development.