How large scale asymmetries in geospace are produced and removed

Abstract:

An unresolved and fundamental problem in space science is to understand the dynamical behavior of the asymmetric geospace. The main driver of the system is the solar wind and the interplanetary magnetic field (IMF). As the IMF orientation is most often transverse, the most common state of geospace involves both dayside-, tail- and lobe-reconnection. In this situation, the northern and southern hemispheres respond differently in terms of the loading, or redistribution, of flux in the lobes, which induces asymmetries between the hemispheres as are observed in asymmetric aurora, convection patterns and current systems.

It has been suggested that asymmetries can be introduced to the closed magnetosphere through tail reconnection. Based on simultaneous imaging of the aurora in both hemispheres, as well as in-situ measurements of plasma flows in the lobes, we have shown that tail reconnection has rather the opposite effect, it removes asymmetries.