FINITE-ELEMENT NUMERICAL MODELING OF STATIONARY 2-DIMENSIONAL MAGNETOSPHERE WITH DEFINED BOUNDARY

A finite element numerical procedure is developed for two-dimensional modeling of stationary magnetosphere. The whole magnetic field is supp osed to be a sum of given internal fields and a searched divergent-fre e and curl-free field of the magnetopause shielding current system, Th e boundary condition on the given boundary is the Neumann one on the m agnetopause part of the computational region boundary and the Dirichle t condition on the segment part, closing this region at the tail. The algorithms used for automatic grid generation and grid transformation allow wide flexibility in determining the region shape and the assigne d internal fields. Some numerical implementations not only demonstrate the method capabilities. In the frame of the two-dimensional approach these implementations could be considered as a tentative simulation o f some typical features of magnetosphere magnetic field topology, whic h is intrinsically three-dimensional. The magnetopause geometry influe nce on the cusp inclination is shown. The impact of the northward and the flow-aligned field on dayside merging and tail asymmetry is alumin ized. A two-dimensional approach to modelling the crosstail currents i s proposed for the Earth-type and Uranus-type magnetospheres. (C) 1995 Academic Press, Inc.