**FULL TITLE** ASP Conference Series, Vol. **VOLUME**, **YEAR OF PUBLICATION** **NAMES OF EDITORS** Physical, Numerical, and Computational Challenges in Modeling the Geospace Environment

Abstract. We present a high level overview of Earth's immediate space environment, called geospace, and contemporary eorts to model it. As with the modeling of many complex, multi-scale systems one faces the challenges of limited physical understanding of the system and its processes, less-than-ideal numerical procedures, and computer limitations. In spite of these diculties, advanced modeling of geospace is important, because geospace is the only large-scale plasma physical system that is accessible to detailed in situ measurements, and because its variability, \Space Weather", has a substantial impact on human activities in space and on the ground. As an example of state-of-the-art geospace modeling we discuss the global modeling of magnetotail turbulence. 1