IMF B_y Effects on the Strength and Latitude of Polar Electrojets: CHAMP and Swarm Joint Observations

Abstract

In this study, the impact of the interplanetary magnetic field (IMF) B_y component on the peak strength and position of polar electrojets (PEJs) is analyzed, based on 16 years of joint observations from Challenging Minisatellite Payload (CHAMP; 2000–2010) and Swarm (2014–2020) satellites, while focusing on the local time and hemispherical differences. With a more positive IMF B_y, the duskside eastward PEJ enhances significantly at June solstice in the Northern Hemisphere. Around midnight, the impact of IMF B_y on the PEJ is more significant in the winter hemisphere; the westward PEJ is stronger in the Northern (Southern) Hemisphere for a more positive (negative) IMF B_y. In 03–08 MLT, the impact of IMF B_y is similar in both the winter and summer hemispheres: for IMF B_y > 0 and B_y < 0, the PEJ in the dawn sector is stronger in the December and June solstices, respectively. Around noon, a more duskward (dawnward) IMF B_y component leads to a higher eastward (westward) PEJ in the northern (southern) summer hemisphere. The northern westward (eastward) PEJ peaks at higher latitudes than the southern PEJ for a negative (positive) IMF B_y.