The Effect of Recirculated Plasmasphere Material: Its signatures and how it interacts with the Ring Current.

The fate of flux tube material once it is drained out of the plasmasphere through a plume is unknown. One of two things may happen to the vented plasmasphere material. It can be either swept away by the solar wind and lost to the earth system or recirculated into the magnetosphere system. Recirculating plasmasphere material could plausibly enter the central plasma sheet and contribute to the ring current. Using observations to study the fate of the plasmasphere material is difficult as it is mostly hydrogen making it challenging to distinguish from the solar wind with in situ observations. Numerical models, however, can keep the material distinct, opening the possibility of resolving the question using simulations.

This work uses numerical models to answer three questions: First, does any plasmasphere material recirculate back into the magnetosphere? Second, what effect, if any, does this additional material have on the formation of the ring current? Third, what signature can we look for in real world data to distinguish if this is a physical or model effect? This is done by studying simulations produced by the Space Weather Modeling Framework configured to couple three models: the Block Adaptive Tree Solar Roe Up Wind Scheme, the Comprehensive Inner Magnetosphere-Ionosphere (CIMI) model, and the Ridley Ionosphere Model. We have added a second population in CIMI representing the portion of the plasmasphere which both recirculates and contributes directly to ring current material. With this new capability we can self-consistently model the ring current and see what portion of observables such as density, momentum, and pressure come from the recirculating plasmasphere material. The study will be conducted across several simulations including: an ideal square wave storm, a corotating interaction region event, and two coronal mass ejection storms.