Effect of Interplanetary Magnetic Field Bx on the Polar Electrojets As Observed by CHAMP and Swarm Satellites

Based on 16 years of magnetic field observations from CHAMP and Swarm satellites, this study investigates the influence of the Interplanetary Magnetic Field (IMF) Bx component on the location and peak current density of the polar electrojets (PEJs). We find that the IMF Bx displays obvious local time, seasonal, and hemispherical effects on the PEJs, as follows: (1) Compared to other local times, its influence is weakest at dawn and dusk. (2) In the midnight sectors of both hemispheres, the IMF Bx tends to amplify the westward PEJ when it is <0 in the Northern Hemisphere and when it is >0 in the Southern Hemisphere; this effect is relatively stronger in the local winter hemisphere. (3) At noontime, the IMF Bx intensifies the eastward current when it is <0 in the Northern Hemisphere; in the Southern Hemisphere when it is >0, it reduces the westward current; this effect is notably more prominent in the local summer hemisphere. (4) Moreover, the noontime eastward current shifts towards higher latitudes, while the midnight westward current migrates towards lower latitudes when IMF Bx is <0 in the Northern Hemisphere and when it is >0 in the Southern Hemisphere.