Studying Longitudinal Inhomogeneities of the Ionospheric and Geomagnetic Disturbances in the Northern Hemisphere during Magnetic Storms

Longitudinal structure of the geomagnetic field variations during severe magnetic storms and under quiet geomagnetic conditions in 2015 is studied based on two magnetometer chains in the Northern Hemisphere located near ~55°N and 70°N. It has been found that longitudinal structure of the geomagnetic field variability is irregular due to the difference of geographic and geomagnetic poles and also, due to the existence of anomalies of different spatial scales in the background magnetic field of the Earth. Features of the geomagnetic field longitudinal variations also strongly depend on individual characteristics of magnetic storms. Analysis of data from the midlatitude Eurasian chain of vertical sounding ionosondes shows that the registered ionospheric effects also exhibit pronounced longitudinal inhomogeneity associated with the presence of longitudinal features of the geomagnetic field background structure and variations during magnetic storms. We assume that the storm-associated ionosphere dynamics is determined by the lower thermosphere disturbances due to the auroral electrojet amplifications producing the enhanced neutral wind and turbulences. These processes, in turn, uplift the molecular gas to the ionospheric heights, decreasing the [O]/[N
₂
] ratio and, therefore, the electron density.