Ionospheric Density Irregularities at Equatorial Plasma Depletion: Synthetic Aperture Radar Satellite Observation

Abstract

We present observation of plasma density irregularities in the equatorial ionosphere by using Synthetic Aperture Radar (SAR) satellite and ground all sky imager. In the vicinity of observed 630-nm airglow depletion in northern Brazil, the ALOS-2/PALSAR-2 satellite image shows stripe-like distortions of SAR signal power that are aligned in the direction of local magnetic field lines. We show that these phenomena called SAR scintillation stripes, which were first reported a decade ago, are caused by plasma irregularities with the scale size of hundreds of meters associated with equatorial plasma bubbles. The spatial distribution of extracted scintillation stripes and SAR-derived density gradients are analyzed. This study suggests SAR satellite data can be used to image equatorial plasma irregularities with high spatial resolution