Plasmasphere Data Assimilation and Comparison With In-Situ Observations

The Earth's plasmasphere is a dynamic region of dense plasma with its

source in the ionosphere. Accurate knowledge of the plasma density

distribution and boundaries are important for the accurate modeling of

the radiation belts and ring current growth and decay mechanisms. The

plasmasphere densities can be determined in many ways, from space and

from the ground. However almost all such observations are limited to

point observations or single flux tube observations. For complete

knowledge the regions between observations must be filled in with a

model. The combination of a model with observations to obtain an

optimal global map is called data assimilation. We will show some

results which combine a simple plasmasphere model, the Dynamic Global

Core Plasma Model with a variety of observations in an Ensemble

Kalman Filter framework to produce maps of the global plasma density

dynamics. These maps are then compared with in-situ spacecraft

observations for validation.