A model of solar wind-magnetosphere-ionosphere coupling for due northward IMF

A solar wind-magnetosphere-ionosphere coupling model for due northward IMF is proposed. The magnetosphere couples with the solar wind through reconnec tion nightside of the cusps. Other than;the two small regions where reconne ction takes place the magnetosphere is closed. There are three plasma regio ns in the magnetosphere. The inner core is dominated by corotation. The out er magnetosphere contains two convection cells, and-maps to the ionospheric viscous cells and Region I currents. The boundary layer and magnetotail re gion consists of a pair of flow channels, and maps to the ionospheric rever se cells. The three regions are separated by separatrix surfaces. Energy co upling across the surfaces can be facilitated by non-ideal-MHD processes su ch as ionospheric coupling, viscous and diffusive interactions, and waves a nd instabilities, although only the ionospheric coupling is essential to th e model. This model is consistent with most established characteristics fro m observations and MHD computer simulations in both the ionosphere and magn etosphere. :There are two specific features that need to be further confirm ed from observations. The model expects that the ionospheric NBZ currents a nd reverse cells are maximized in the region sunward of the pole near the d ayside cusps, and that in the tail there is a region which separates the ea rthward and tailward flows although the held and plasma characteristics are magnetospheric on both sides. (C) 1999 Elsevier Science Ltd. All rights re served.