Title:  Investigation of ionospheric dynamics during geomagnetic storm and solar eclipse events

Abstract:  Upper atmospheric variability remains a primary challenge for accurate specification and prediction of ionospheric behavior and a focus of substantial research effort. My seminar will discuss two recent studies addressing ionospheric disturbances related to different driving forces. In the first study, we used multiple instruments and modeling tools to investigate the ionospheric changes during geomagnetically disturbed period, with focus on variations in Traveling Ionospheric Disturbances (TIDs). Our results show how TID behavior varies with different background plasma density during different geophysical conditions. Results also show the transfer of energy and momentum from one hemisphere to another and how TID properties could be substantially affected by storm time background neutral wind perturbations. In the second study, we show that the ionosphere varies significantly during solar eclipse. In a case study of July 2019 solar eclipse that occurred mostly over the Pacific Ocean, our analysis reveals both significant reduction and enhancement of electron density around the EIA (Equatorial Ionization Anomaly) crest and sub-EIA crest, respectively. The increase in the electron density is associated with the enhancement of the fountain effect, vertical plasma drift and electrojet at the magnetic equatorial region while the reduction is a result of the lower photoionization due to the eclipse event. Finally, we found a domineering TEC bite-out near the EIA crest soon after the eclipse onset.