The role of the inner tail to midtail plasma sheet in channeling solar wind power to the ionosphere

Abstract

In this article we use Cluster power density (E·J) data from 2001, 2002, and 2004 to investigate energy conversion and transfer in the plasma sheet. We show that a southward IMF Bz is favorable for plasma sheet energy conversion, and that there is an increased particle and Poynting flux toward the Earth at times when Cluster observes an enhanced energy conversion in the plasma sheet. Conversion from electromagnetic to kinetic energy is increasingly dominant farther down-tail, while the generation of electromagnetic power from kinetic energy becomes important toward the Earth with a maximum at roughly 10 RE. By linking observations of the key quantity E·J to observations of the solar wind input and earthward energy flux, our results demonstrate the role of the inner tail to midtail plasma sheet as a mediator between the solar wind energy input into the magnetosphere and the auroral dissipation in the ionosphere. © 2012. American Geophysical Union. All Rights Reserved.