1] Based on the space-time conservation element and solution element (CESE) method, we have recently developed a novel 3D magnetohydrodynamic (MHD) model for the solar corona and interplanetary study. Our aim here is to describe the application of this new MHD model to study the global coronal magnetic structures by using the observed line-of-sight photospheric magnetic field from the Wilcox Solar Observatory (WSO) as boundary conditions. With this model, the magnetic structures of the global corona are obtained for fifteen Carrington Rotations (CRs) spanning solar cycle 23. The results illustrate how the shape and location of the heliospheric current sheet (HCS) and the coronal magnetic field configuration evolve during the course of the solar cycle. Comparison between our numerical results for the coronal magnetic structures and those from the standard potential field source surface (PFSS) model, with, in addition, whitelight observations further validates this new MHD model. The source surface neutral lines calculated from the MHD and PFSS models generally match each other closely; however, differences occur at different phases in the solar cycle. The location of the HCS shows good overall agreement with the bright structures in the observed white-light intensity pattern, especially around solar minimum or well after solar maximum, and this result confirms that the observed white-light streamer structures originate from a single, largescale plasma sheet located near the HCS.

In this paper, the Space-Time Conservation Element and Solution Element (CESE) method is applied to 2.5-dimensional resistive magnetohydrodynamics (MHD) equations in Cartesian coordinates, with the purpose of modeling the magnetic reconnection study. To show the validity and capacity of its application to MHD reconnection problem, spontaneous fast reconnection and magnetic reconnection in multiple heliospheric current sheets are studied, which show good consistency with those obtained formerly by other authors. In order to assess the ∇ · B = 0 constraint numerically, the contours and evolution of ∇ ·B are analyzed. The numerical results tell us that the CESE numerical scheme not only has good numerical resolution but also can keep the divergence-free condition for magnetic fields in the reconnection problems during the evolutionary process without any special treatment.