Dynamics of the Ionospheric Electric Currents and Auroral Luminosity Boundaries during Strong Magnetic Storms

摘要

The regularities in the southward drift of the ionospheric current centers and luminosity bound_aries during strong magnetic storms of November 2003 and 2004 (with Dst≈-400 and -470 nT, respectively) are studied based on the global geomagnetic observations and TV measurements of auroras. It has been indicated that the eastward and westward electrojets in the dayside and nightside sectors simultaneously shift equatorward to minimal latitudes of φ_(min)°～ 53°-55°. It has been obtained that the latitude decreases with increasing negative values of Dst, IMF B_z component, and westward electric field strength in the solar wind. The dependence of the electrojet equatorward shift velocity (V_(av)) on the rate of IMF B_z variations (ΔB_z/Δt) has been determined. It is assumed that the electrojet dynamics along the meridian is caused by a change in the structure of the magnetosphere and electric fields in the solar wind and the Earth's magneto-sphere.