Simulating Polar Cap Ionosphere F-Region Peaks: Investigating Physical Drivers of Lifting

Transport parallel to magnetic field lines in the polar cap ionosphere is a highly dynamic process that varies significantly with geophysical activity and location within the polar cap. The parallel transport can be so significant that ground-based observations, such as those from incoherent scatter radar (ISR) stations, can observe F-region peaks lifted to altitudes exceeding 400 kilometers. The underlying physical drivers and predictors for this lifting are poorly understood. This study investigates these physical drivers utilizing the High-latitude Ionospheric Dynamics for Research Applications (HIDRA) model supported by the Center for Geospace Storms. We utilize the HIDRA model to retrace plasma parcel trajectories throughout the polar cap ionosphere to quantify the chemical and transport-driven density changes throughout their lifespan. This retracing process is applied across moderate to high-activity geomagnetic storms. We utilized solar wind data from the NASA OMNIWeb database to drive the Multiscale Atmosphere Geospace Environment (MAGE) model, and the high-latitude convection and precipitation from MAGE drive our HIDRA simulations. We can then retrace the flux-tube history of plasma parcels through the HIDRA model using the time-evolving velocity field and evaluate the chemical and physical processes governing the evolution of the ion and electron densities, as well as parallel transport, through these varying flux-tube histories.