Modeling the O+ Transit from Ionosphere to Plasmasheet

Abstract:

The ion population in the magnetospheric lobes may play an important role as a seed population for the O+ in the plasmasheet and ultimately in the ring current during active times. It is not clear what is the pathway of ionospheric oxygen to the ring current and what are the mechanisms responsible for their transit from the ionosphere in the time scales observed. A more complete understanding of the nature of this transport mechanism for ions, in particular of O+, is essential to understanding plasmasheet and ring current dynamics. We present a modeling effort based on a 3D MHD global magnetosphere code (LFM), coupled with a guiding center test particle code to explore an O+ activity-dependent transport path from the ionosphere to the plasmasheet and the effects of the O+ in transit between these two regions during transitions from quiet to storm times. The overarching scientific objective of this investigation is to understand and quantify through test particle simulations the dynamics of this transport. A better understanding of this transport mechanism could improve large-scale magnetospheric models that can in turn be used to investigate the effects of energetic O+ on ring current dynamics.