Modeling Magnetospheric Plasma Processes

Modeling Magnetospheric Plasma

Published by the American Geophysical Union as part of the Geophysical Monograph Series, Volume 44. Existing models of the plasma distribution and dynamics in magnetosphere / ionosphere systems form a patchwork quilt of different techniques and boundaries chosen to define tractable problems. With increasing sophistication in both observational and modeling techniques has come the desire to overcome these limitations and strive for a more unified description of these systems. On the observational side, we have recently acquired routine access to diagnostic information on the lowest energy bulk plasma, completing our view of the plasma and making possible comparisons with magnetohydrodynamic calculations of plasma moments. On the theoretical side, rising computational capabilities and shrewdly designed computational techniques have permitted the first attacks on the global structure of the magnetosphere. Similar advances in the modeling of neutral atmospheric circulation suggest an emergent capability to globally treat the coupling between plasma and neutral gases. Simultaneously, computer simulation has proven to be a very useful tool for understanding magnetospheric behaviors on smaller space and time scales.

Modeling Magnetospheric Plasma Processes

Modeling Magnetospheric Plasma Processes

Published by the American Geophysical Union as part of the Geophysical Monograph Series, Volume 62. The ultimate goal of modeling of the plasma in Earth's environment is an understanding of the magnetosphere and ionosphere as a coupled global system. To achieve this goal requires a coordinated effort between models applied to different spatial scales. The desire to model this system on a global scale is leading to models which encompass larger and larger regions. The ever-increasing availability of computing resources has allowed models to expand to 2 and 3 dimensions. At the other extreme are the micro-scale processes which transfer energy to individual particles within the global system. As more detailed observations become available the necessity for accurately including such processes in the global models becomes more apparent. Then it becomes a question of how to incorporate the necessary physical processes from all scale sizes into a model of a global system. It now seems clear that such multi-scale scenarios exist where micro-scale processes provide energy to the plasma which flows outward from Earth into the distant magnetotail before returning to the near-Earth regions. The challenge of incorporating all relevant processes into a model of this entire plasma path is a formidable one. The existence of separate models of the separate steps along this pathway leads directly to efforts to fuse models with different scales into a single, self-consistent treatment.