Total Electron Content Disturbances Driven by Solar Wind Ultra Low Frequency Oscillations on 3 December 2021

The ionospheric impact of the solar wind oscillations in the Ultra Low Frequency (ULF) period range of several minutes to tens of minutes is not well understood. In the ULF range, acoustic-gravity waves from the lower atmosphere can also induce ionospheric disturbances. The source differentiation for the ionospheric disturbances, especially from the Global Navigation Satellite System (GNSS) Total Electron Content (TEC) observations, remains a challenge. We investigate the TEC response to the solar wind ULF oscillations on 3 December 2021 using GNSS observations and physics-based modeling. During the time interval of interest, GNSS observations reveal significant TEC disturbances with tens-of-minute periods at geomagnetic conjugate locations in North America and in Antarctica. With numerical modeling, we identify the ULF oscillations of the interplanetary magnetic field (IMF) to be the main cause of the TEC disturbances. Moreover, our modeling experiment of lower-atmospheric-driving reveals the spectral frequency difference between the TEC disturbances driven by the solar wind ULF oscillations and the TEC disturbances driven by the lower atmospheric acoustic-gravity waves, which sheds light towards identifying sources responsible for the TEC disturbances observed by GNSS.