North-South Asymmetries in Earth's Magnetic Field: Effects on High-Latitude Geospace

Abstract

The solar-wind magnetosphere interaction primarily occurs at altitudes where the dipole component of Earth's magnetic field is dominating. The disturbances that are created in this interaction propagate along magnetic field lines and interact with the ionosphere-thermosphere system. At ionospheric altitudes, the Earth's field deviates significantly from a dipole. North-South asymmetries in the magnetic field imply that the magnetosphere ionosphere-thermosphere (M-I-T) coupling is different in the two hemispheres. In this paper we review the primary differences in the magnetic field at polar latitudes, and the consequences that these have for the M-I-T coupling. We focus on two interhemispheric differences which are thought to have the strongest effects: 1) A difference in the offset between magnetic and geographic poles in the Northern and Southern Hemispheres, and 2) differences in the magnetic field strength at magnetically conjugate regions. These asymmetries lead to differences in plasma convection, neutral winds, total electron content, ion outflow, ionospheric currents and auroral precipitation.

References in corpus (4)

• Seasonal and diurnal variations in AMPERE observations of the Birkeland currents compared to modeled results
• Intensity asymmetries in the dusk sector of the poleward auroral oval due to IMF $B_x$
• Birkeland current effects on high-latitude groundmagnetic field perturbations
• What is the appropriate coordinate system for magnetometer data when analyzing ionospheric currents?

Cited by in corpus (5)

• Observations of Asymmetries in Ionospheric Return Flow During Different Levels of Geomagnetic Activity
• Toward a Next Generation Particle Precipitation Model: Mesoscale Prediction Through Machine Learning (a Case Study and Framework for Progress)
• Interplanetary Magnetic Field $B_x$ Component Influence on Horizontal and Field-Aligned Currents in the Ionosphere
• Magnetic Effects of Plasma Pressure Gradients in the Upper F Region
• Ionospheric responses over the Antarctic region to Intense Space Weather events: Plasma Convection vs. Auroral Precipitation