Abstract:
Geomagnetic storms of G1-class were observed on 3 and 4 February 2022, which caused the loss of
38 out of 49 SpaceX satellites during their launch due to enhanced neutral density. The efects of
storm-time neutral dynamics and electrodynamics over the American sector during this minor storm
have been investigated using Global Positioning System—total electron content (TEC) and Global‐
scale Observations of the Limb and Disk (GOLD) mission measured thermospheric composition and
temperature. Results revealed an unexpected feature in terms of increase in O/N2 and depletion in
TEC over the American low-latitudes. This feature is in addition to the classic storm time ionospheric
variations of enhancement in ionospheric electron density in presence of enhanced O/N2 and an
intense equatorial electrojet (EEJ). Further, signifcant morning-noon electron density reductions
were observed over the southern mid-high latitudes along the American longitudes. Results from
Multiscale Atmosphere-Geospace Environment (MAGE) model simulations elucidated storm-induced
equatorward thermospheric wind which caused the strong morning counter electrojet by generating
the disturbance dynamo electric feld. This further explains the morning TEC depletion at low-latitudes
despite an increase in O/N2. Sub-storm related magnetospheric convection resulted in signifcant
noon-time peak in EEJ on 4 February. Observation and modelling approaches together suggested that
combined efects of storm-time neutral dynamic and electrodynamic forcing resulted in signifcant
ionospheric variations over the American sector during minor geomagnetic storms.
