Global-MHD Simulations Using MagPIE: Impact of Flux Transfer Events on the Ionosphere

This study presents a recently developed two-way coupled magnetosphere-ionosphere model named "MagPIE" that enables the investigation of the impact of flux transfer events (FTEs) on the ionosphere. Our findings highlight the prominent role of cusp-FTE reconnection in influencing the ionosphere. The typical morphology of an FTE signal, represented by field-aligned currents (FACs) on the ionosphere, is shown to exhibit a distinct pattern characterized by an "I"-shaped patch surrounded by a "U"-shaped patch. Furthermore, we demonstrate that the effects of FACs resulting from FTEs may extend well into the region of closed field lines on the ionosphere. These FACs are seen to exhibit a remarkable resemblance to discrete dayside auroral arcs, providing further evidence that FTEs can be considered as a probable cause of such phenomena. Additionally, FTEs generate vortex-like patterns of ionospheric flow, which can manifest as either twin vortices or a combination of multiple vortices, depending on the characteristics of the FACs producing them. Furthermore, we present compelling evidence of morphological similarities between the simulated ionospheric signatures obtained from the MagPIE model and an observation made by the SWARM satellites. The agreement between our model and observational data further strengthens the credibility of our model and opens up new avenues to theoretically explore the complex ionospheric effects caused by FTEs. We introduce a new numerical model called "MagPIE" that facilitates the understanding of how events in space called flux transfer events (FTEs) affect the Earth's ionosphere. The Earth's magnetosphere comprises of the northern and the southern polar cusps. The study shows that a particular type of interaction between FTEs and the polar cusps, called cusp-FTE reconnection, has a significant impact on the ionosphere. When cusp-FTE reconnection occurs, it imposes a specific imprint of plasma currents on the ionosphere that look like an "I" shape surrounded by a "U" shape. These currents have effects beyond the immediate area where the FTEs connect to the ionosphere. The shape of these currents in the ionosphere is similar to how discrete bright auroral arcs appear in the polar regions, which suggests that FTEs could be a cause of these auroral phenomena. It is seen that these currents produced by "MagPIE" model are similar to an observation made by ionospheric satellites which strengthens the reliability of the model and provides new opportunities for exploring the complex effects of FTEs on the ionosphere.