The asymmetric magnetosphere

Abstract:

When a sphere is put into a streaming gas, one would expect the diversion of the flow to be fairly rotationally symmetric about the flow direction. In the solar-wind-magnetosphere interaction, there are a number of processes that can break this symmetry. Some of the asymmetries can be attributed to pure mechanics of the Earth's celestial motion or intermittent structures in the solar wind, but some of the asymmetries are persistent. In this presentation we focus on observations from the terrestrial magnetopause which show a persistent dawn-dusk asymmetry in key parameters such as current density, thickness and motion of the magnetopause current sheet. We also show examples on how dawn-dusk asymmetries in the magnetosphere can set up corresponding north-south asymmetries and how these are coupled to the high latitude ionosphere.