Energy Flow in the Geomagnetic Tail

MHD closure of the moment equations neglects the divergence of the off-diagonal elements of the stress tensor, Π , as well as the divergence of heat flux ∇ q. In the center of the plasma sheet the local ion gyroradius becomes large, and q and Π become important components of the current sheet energy and momentum balance. Previous work^[1] showed that the heat flux, q, plays in important role in substorm dynamics by allowing the non-adiabatic cooling of the magnetotail. The present work will discuss results from large-scale particle simulations with enough particles to resolve the heat flux term in three dimensions.l [1] Doxas, I., W.~Horton and R.~Weigel, Using Particle Simulations for Parameter Tuning of Dynamical Models of the Magnetotail, JASTP 64, 633 (2002).