Relationship between the midnight equatorward auroral oval boundary and the geomagnetic activity level for different solar wind regimes,

For a better understanding of auroral phenomena it is necessary to evaluate in detail the magnetospheric/ionospheric response to different solar wind triggers. The equatorward magnetic latitude of the auroral oval midnight sector (MLat), detected by the Defense Meteorological Satellite Program (Cedarweb), was investigated for different solar wind conditions during the ascending phase of the on-going solar activity cycle (n. 23). The correlation between MLat and each one of the geomagnetic indices was performed separating corotating from transient plasma streams. Moreover the correlation was repeated considering also the interplanetary parameters variability (e.g. solar wind speed, pressure and density, magnetic field intensity, dawn-dusk electric field, etc.). It was found that MLat depends on the solar wind regimes in different ways. An attempt to derive useful algorithms for auroral forecast works was initiated and some results are shown.