Heavy Ion Effects on Magnetotail Stability in Global Multi-Fluid MHD Simulations

Ionospheric O+ outflow into the plasma sheet changes properties of reconnection and affects the circulation of magnetic flux and plasma through the magnetotail. These changes in transport in turn affect the circulation of heavy ions and their entry into different regions of the magnetosphere. Changes in magnetotail transport include large scale dipolarizations associated with substorms and more isolated, elementary dipolarizations associated with bursty bulk flows, both carrying magnetic flux and plasma into the inner magnetosphere. Here we carry out an analysis of the simulated magnetotail from results of multi-fluid global MHD coupled self-consistently with an ionospheric outflow and thermosphere model (the coupled MFLFM-IPWM-TIEGCM models). We examine two MHD instabilities from the point of view of the isotropic magnetotail stability theory: flux tube entropy-controlled interchange instability and the magnetic flux release instability (MFRI), both of which may occur due to tailward gradients of Bz in the magnetotail. We examine the differences in magnetotail stability parameters in global MHD with varying amounts of ion outflow, in order to shed light not only on the effects of outflow on the tail stability but also the processes through which heavy ion outflow may affect ensuing plasma sheet flow dynamics.