Role of the external drivers in the occurrence of low-latitude ionospheric scintillation revealed by multi-scale analysis

In the low latitude ionosphere, the formation of Equatorial Plasma Bubbles presents a regular behavior under quiet conditions ofthe geospace. The ionospheric irregularities embedded in the plasma bubbles may lead to amplitude scintillation of Global Navigation Satellite Systems signals. Solar events disturb the regular behavior of the magnetosphere-ionosphere system, leading to an intensification or a suppression of such ionospheric irregularities producing scintillations. During the same storm, inhibition and intensification ofthe ionospheric scintillations can both occur, depending on the local time ofthe storm arrival and on the storm features. Electric fields penetrating from the auroral latitudes and disturbing the ionospheric electrodynamics are commonly highlighted as the principal responsible for the inhibited/enhanced scintillations. Beside this mechanism, the disturbance dynamo is the concurrent key-physical phenomenon, being due to variations ofthe thermospheric winds induced by heating convecting from high towards equatorial latitudes and disturbing the electrodynamics ofthe Equatorial Electrojet [1]. In the present work, we analyze the scintillation over San Miguel de Tucumán (Argentina), located under the southern crest ofthe Equatorial Ionospheric Anomaly, focusing on the multi-scale variability and on the causal relationship between forcing factors from the geospace and the ionospheric response.