Sudden stratospheric warmings (SSWs) are impressive fluid dynamical events in which large and rapid temperature increases in the winter polar stratosphere (∼10–50km) are associated with a complete reversal of the climatological wintertime westerly winds.
The flow of ionospheric current can be probed by examining magnetic field measurements at the ground and at Low-Earth-Orbit (LEO) altitude.
During geomagnetic disturbances, enhanced high‐latitude convection transports ionospheric F2‐region plasma from the dayside midlatitude region into the polar cap, leading to structures such as tongues of ionization (TOIs) and patches.
Recently, there have been some reports of unusually strong photospheric magnetic fields (which can reach values of over 7 kG) inferred from Hinode SOT/SP sunspot observations within penumbral regions.
We conduct observational and modeling studies of thermospheric composition responses to weak geomagnetic activity (non-geomagnetic storms). We found that the thermospheric O and N 2 column density ratio (∑O/N 2 ) in part of the Northern Hemisphere measured by
