Dynamics of the ionospheric electric currents and auroral luminosity boundaries during strong magnetic storms

The regularities in the southward drift of the ionospheric current centers and luminosity boundaries during strong magnetic storms of November 2003 and 2004 (with Dst a parts per thousand -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 I broken vertical bar (min) (A degrees) similar to 53A degrees aEuro"55A degrees. It has been obtained that the I broken vertical bar (min) (A degrees) 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 (Delta B (z) /Delta t) 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 magnetosphere.