Wednesday, March 29, 2023 - 3 p.m. to 4 p.m.
Zoom online
Speaker: Laysa Resende - State Key Laboratory for Space Weather and National Institute for Space Research
Full Title: Study of the Atypical Sporadic E (Es) layer Development over the Brazilian Sector
Abstract: E region electric fields, particle precipitation, and instabilities during quiet and disturbed periods can cause anomalous Es layer behavior, which is observed in the digital ionosonde data. To investigate the Es layer behavior, we analyzed set days around magnetic storms from 2015 to 2018 over Boa Vista (BV, 2.8°N, 60.7°W), São Luís (SLZ, 2.3°S, 44.2°W), and Cachoeira Paulista (CXP, 22.41°S, 45°W). The electric field zonal components during each magnetic storm's main and recovery phases are computed to study the corresponding characteristics of these Es is seen in ionograms. The results sustain that the strong Es layer in BV can be an indicator of the disturbed dynamo event. At SLZ, on the other hand, the Es layers are affected by the competition mechanisms of their formation, as equatorial electrojet (EEJ) irregularities and winds, during the main phase of the magnetic storm.
Over CXP, the wind shear mechanism dominates the Es layer dynamics. Additionally, in this region, the inhomogeneous Es layer is associated with the auroral-type Es layer (Esa) occurrence due to the presence of South American Magnetic Anomaly (SAMA). However, we also observe that the spreading Es layers occurred days before the magnetic storms or quiet times. Thus, our results lead us to believe other mechanisms affect the Es layer development in CXP. We show evidence that the instabilities added to the wind shear mechanism can cause the atypical Es layers, such as Kelvin-Helmholtz instability (KHI). Finally, this study provides new insights into the real impact of the electric field in the Es layer development over the Brazilian sector
Schedule: Check out the rest of this season's Space Science Seminar Series, as well as previous recordings.
