Low frequency (1-4 MHz) geomagnetic field fluctuation power - Latitudinal dependence and relation with solar wind parameters

We present a statistical analysis of the low frequency geomagnetic field fluctuation power over a very wide latitudinal extension. At latitudes up to 60 deg the local time and seasonal dependence indicate a strong ionospheric influence while at higher latitudes an important role is played by the substorm occurrence and the position of the station with respect to the polar cusp. The latitudinal distribution of the fluctuation power gives an indication of the cusp position, which has been found to move from less than 75 deg to more than 80 deg, depending on season and interplanetary conditions. Lastly, the fluctuation power is strongly related to the solar wind speed and, at latitudes between 60 and 70 deg, to the north-south component of the interplanetary magnetic field.