TALK ABSTRACT:
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Global MHD numerical simulation codes provide a useful tool for studying
the coupling of energy and momentum from the solar wind to the Earth's
magnetosphere.  This presentation will address the relevance of the MHD
approximation and its application to the magnetosphere-ionosphere system.
We will consider the coupling process, the source of magnetospheric
convection, and the current systems which link the solar wind through the
magnetosphere to the ionosphere.  A crucial controlling parameter in these
processes is the direction of the interplanetary magnetic field relative
to the geomagnetic field, because it determines the entry of solar wind
electromagnetic energy into the magnetospheric system.  Examples of how
this occurs will be shown and its role in magnetospheric dynamics will
be discussed.  Comparisons between in situ spacecraft measurements and
numerical simulation results will be presented.  Finally, we will outline
directions for future model development and research studies.