A Statistical Study of Field-Aligned Currents During BBF and Non-BBF Periods

The coupling between the mid-magnetotail and the high-latitude ionosphere is driven by dynamic processes such as earthward bursty bulk flows (BBFs), which facilitate plasma transport to the inner magnetosphere. These flows interact with the ionosphere through Field-Aligned Current (FAC) systems. This work investigates the relationship between BBFs and FACs by utilizing nearly a decade of ionospheric measurements from the Swarm constellation, complemented by data from magnetospheric missions, particularly the Magnetospheric Multiscale (MMS) Mission. Approximately 2000 BBFs detected during the MMS tail seasons from 2017 to 2021 were mapped onto the ionosphere using Tsyganenko models. The mapping revealed a statistically consistent pattern of BBF footpoints between 65° and 75° magnetic latitude and 20 to 04 hour MLT, with a peak in the pre-midnight sector. To examine the connection between BBFs and ionospheric currents, we compared these footpoint locations with statistical maps of Swarm-derived FACs during BBF and non-BBF periods. We further analysed whether BBF periods correspond to significant changes in FACs. This approach aims to uncover the relationship between BBF mapping points and FAC dynamics, providing insights into the magnetosphere-ionosphere coupling processes.