Dynamics of the auroral electrojets and their mapping to the magnetosphere

Data of the EISCAT and IMAGE magnetic observatories chains in combination w ith data of three Russian observatories (St. Petersburg, Borok and Moscow) were used to determine the eastward and westward electrojet dynamics in the course of magnetic storms. During the storm main phase and maximum substor m intensity the eastward electrojet is located at latitudes lower than usua l. During intervals between substorms the westward electrojet centre shifts equatorwards as Dst increases. At a substorm maximum the westward electroj et widens polewards. The spectrograms of precipitating electrons and ions o f auroral energies obtained onboard the DMSP F8, F10 and F11 satellites all ow to connect the regions of the electrojet location with characteristic pl asma structures at ionospheric altitudes. The eastward electrojet in the ev ening sector is located in the region of diffuse electron precipitations. T he electrojet centre coincides with the latitude of an energy flux maximum of auroral protons. In the course of substorms the westward electrojet at t he nightside is located at latitudes of both diffuse and discrete electron precipitations. The electrojets and plasma region boundaries are mapped to the magnetosphere. The paraboloid model of the magnetosphere is used here. The influence of paraboloid model input parameters on the dayside cusp lati tude, on the ionospheric boundaries between open and closed as well as dipo le-like and tail-like field lines is considered. It is shown that tail curr ents influence magnetic field line configuration in the nightside magnetosp here stronger than the ring current. (C) 1999 Elsevier Science Ltd. All rig hts reserved.