(a)–(d) Sequence of several consecutive Swarm B satellite overpasses (magenta line) plotted over GNSS ROTI maps during 17–22 UT on 23 April 2023, along with Swarm in situ electron density (Ne) variations plotted as a function of geographical latitude for the storm day (magenta line) of 23 April 2023 and the reference day (blue line) of 22 April 2023. The thin horizontal line on density plots marks the magnetic equator location.