Detecting near-tail current sheet formation using isotropic boundaries: lessons from global MHD.

Abstract

A number of recent studies suggests an existence of magnetotail current sheet configurations with tailward Bz gradient during the growth phase of the substorm. Such configurations are especially interesting since they are potentially unstable for different types of instabilities and can lead to explosive reconfiguration of the magnetosphere. However, the observations are rare and ability to observe tailward gradients is very limited. Here we use the global MHD configuration with near-tail Bz minimum to investigate the regions with adiabatic and non-adiabatic behavior of energetic particles. Thus we estimate the locations of the isotropic boundaries for the modelled POES-type spacecraft flybys. We expect that the lessons learned from global MHD simulation may become helpful in exploration of non-monotonic tail current sheet configuration using observations on low-orbiting spacecraft.