Browsing by Author "Newheart, Anastasia Michele"

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    The role of magnetospheric convection in the formation of ionospheric structuring and irregularities
    (2022-07-20) Newheart, Anastasia Michele; Toffoletto, Frank; Fejer, Bela G
    In this work, I investigate the effects of magnetospheric convection on ionospheric irregularities. I examine the role of electrodynamics on the equatorial ionization anomaly (EIA), on traveling ionospheric disturbances (TIDs), and on equatorial plasma bubbles. To examine the EIA, we examined the equatorial F-region structure at night using electron density measurements from the ISS Floating Potential Measurement (FPMU) along with Swarm spacecraft electron density measurements and Total Electron Content (TEC) from ground-based GNSS receivers for comparison. During these time periods, the EIA extended to local times late as post-midnight in some cases. To examine the role of high latitude disturbances in TID formation, I utilized spectral analysis of detrended TEC for events with different levels and types of geomagnetic activity to deduce spectral characteristics of observed TIDs and their relationship to the auroral activity at different latitudes and local time sectors. To investigate prompt penetration electric fields and the formation of EPBs, I used numerical simulations with the coupled SAMI3/RCM first-principles model. I used simulation results to examine storm-time electrodynamics and to estimate linear growth rates of the generalized Rayleigh-Taylor instability during major geomagnetic storms. For comparison, I utilized drift velocity measurements from the Jicamarca incoherent scatter radar and observation of plasma bubbles from the FPMU aboard ISS, the Swarm EFI and TEC from GNSS. By comparing calculated growth rates to plasma bubble occurrence, we can examine the role of storm-time electric fields in plasma bubble formation.