1Max-Planck Institute for Solar Systems, Germany
2Department of Physics and Technology, University of Bergen, Norway
3Department of Physics, University of Oslo, Norway
4Norwegian Defence Research Establishment, Norway
5Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Germany
6University of New Hamshire, NH, USA
Received: 20 Jan 2009 – Published: 28 Sep 2009
Abstract. The Earth's magnetosphere is populated by particles originating from the solar wind and the terrestrial ionosphere. A substantial fraction of the plasma from these sources are convected through the magnetotail lobes. In this paper, we present a statistical study of convective plasma transport through the Earth's magnetotail lobes for various geomagnetic conditions. The results are based on a combination of density measurements from the Electric Field and Waves Experiment (EFW) and convection velocities from the Electron Drift Instrument (EDI) on board the Cluster spacecraft. The results show that variations in the plasma flow is primarily attributed to changes in the convection velocity, whereas the plasma density remains fairly constant and shows little correlation with geomagnetic activity. During disturbed conditions there is also an increased abundance of heavier ions, which combined with enhanced convection, cause an accentuation of the mass flow. The convective transport is much slower than the field aligned transport. A substantial amount of plasma therefore escape downtail without ever reaching the central plasma sheet.
Haaland, S., Lybekk, B., Svenes, K., Pedersen, A., Förster, M., Vaith, H., and Torbert, R.: Plasma transport in the magnetotail lobes, Ann. Geophys., 27, 3577-3590, doi:10.5194/angeo-27-3577-2009, 2009.