Reconnection modes for near‐radial interplanetary magnetic field

The principal purpose of the present paper is to report about a new magnetospheric reconnection structure arising for the near‐radial interplanetary magnetic field (IMF) orientations. This structure includes simultaneous existence of two modes of the solar wind‐magnetosphere coupling (two‐ and three‐dimensional reconnections). For the southward IMF two two‐dimensional merging sites exist: one on the noon equatorial magnetopause and the other in the magnetotail. Reconnection takes place along merging line connecting them. As IMF rotates from southward toward a radial orientation, the merging site where lobe fields reconnect becomes three‐dimensional and moves from the tail to the high‐latitude dayside magnetosphere (northward for IMF B x > 0 and southward for IMF B x < 0), while the merging site where interplanetary and closed field lines reconnect remains two‐dimensional arid shifts along the magnetopause from subsolar point to the south for IMF B x > 0 and to the north for IMF B x < 0. In the vicinity of two‐dimensional magnetic null on the magnetopause, reconnection occurs at merging line simultaneously with the three‐dimensional reconnection at the second neutral point in the magnetosphere. For the strong northward IMF two three‐dimensional merging sites exist in the cusp regions of the magnetosphere. Proposed construction is supported by calculations in the paraboloid magnetospheric model.