High-latitude ionospheric convection patterns dependent on the variable IMF orientation

The magnetospheric magnetic field configuration, created by merging, depend s strongly on the interplanetary magnetic field (IMF) orientation.; There a re different types of reconnection: two-dimensional reconnection at a mergi ng line lying within the magnetopause current layer and/or within the magne totail, and three-dimensional reconnection at the magnetic field neutral po int located inside the magnetosphere, earthward of the magnetopause. All or ientations of the IMF are divided into four sectors. For the first sector r econnection of the Dungey-type occurs; for the second one three-dimensional reconnection takes place;at two neutral points inside the magnetosphere; f or the third-one neutral point exists inside the magnetosphere, near the no rthern cusp, and the other is within the Southern magnetopause current laye r. For the fourth sector one neutral point is located earthward of the sout hern magnetopause, and the other-within the northern magnetopause current s heet. The high-latitude northern and southern ionospheric convection patter ns depend upon the solar wind-magnetosphere coupling type and are different for each sector of IMF-orientation. (C) 1998 Elsevier Science Ltd. All rig hts reserved.