# Unveiling the Core Patterns of High-Latitude Electron Density Distribution at Swarm Altitude
## 5 Discussion
The decrease in electron density is most noticeable in the polar regions, where solar radiation is scarce or non-existent during the winter months. There is an intermediate distribution of electron density in the ionosphere's F-layer during the equinoxes, which mark the transition between summer and winter. When compared to other seasons, the moderate solar radiation and temperatures during these times result in a relatively balanced electron density. Therefore, the spatiotemporal pattern of the residues reflects the fluctuations in electron density within the F-layer of the ionosphere throughout the seasons which arise from the complex interplay between solar radiation, atmospheric temperatures, and ionization processes. Figure 5: **(Upper part)**: polar view of residue obtained from the MEMD of electron density distribution during the equinoxes (first row), summer (second row), and winter (third row) under low (left column) and high (right column) geomagnetic activity conditions in the Northern Hemisphere. Maps are represented in the QD-magnetic latitude (MLat) and MLT reference system. The concentric circles are plotted in 10\({}^{\circ}\) intervals, with the outermost circle corresponding to 50\({}^{\circ}\). **(Bottom part)**: residue trend as a function of the magnetic latitude at a fixed MLT value of 12:00 for the three seasons and two levels of geomagnetic activity. The seasonal differences in the spatiotemporal distributions of the residues obtained by decomposing the electron density distributions remain visible during periods of high geomagnetic activity. The spatial and temporal distribution of the electron density within the residue is higher during the summer compared to the winter and equinox seasons. Figure 5 reveals that the average level of electron density is affected by both the season and the level of geomagnetic activity, with notable changes occurring during periods of high geomagnetic activity. The minimum in the density distribution within the polar cap region vanishes, replaced by a single region of maximum electron density spanning the entire polar region that begins around 80\({}^{\circ}\). Additionally, the band of the minimum electron density shifts towards higher latitudes. The residue maps exhibit a minimum region around 75\({}^{\circ}\), with a subsequent displacement towards the polar region of approximately 5\({}^{\circ}\) compared to the quiet condition. The finding that an increase in geomagnetic activity causes an increase in electron density in the F region of the ionosphere is consistent with previous research. This increase in average electron density can be attributed to a number of well-studied and documented factors. One factor is the enhanced energy input from the magnetosphere during periods of geomagnetic activity. Geomagnetic disturbances such as substorms and magnetic storms can lead to the injection of energetic particles into the ionosphere. These particles ionize the neutral particles in the F region, resulting in an increase in electron density. Another factor is the enhancement of electric fields and plasma convection associated with geomagnetic activity. Electric fields generated by the interaction between the solar wind and the Earth's magnetosphere can accelerate charged particles in the ionosphere, leading to increased electron density. Driven by the motion of plasma within the magnetosphere, plasma convection can transport higher-density plasma in the ionosphere from lower latitudes to higher latitudes. Furthermore, increased geomagnetic activity can lead to changes in thermospheric composition and temperature. These changes can affect the ionization and recombination rates in the F region, influencing the electron density. It is important to note that the relationship between geomagnetic activity and electron density in the F region is complex, and varies depending on the circumstances and location.