Geomagnetic effects of interplanetary shock waves during solar minimum (1995-1996) and solar maximum (2000)

In this paper the interplanetary shock wave effects on geomagnetic activity, quantified by the maximum hourly Dst and tri-hourly ap indices, in a period of 3 days after the shock, are evaluated. Correlations between shock parameters and Dst and ap geomagnetic indices during solar minimum (1995-1996) and solar maximum (2000) periods are obtained. It is observed that solar wind speed and total magnetic field variations through the shock are the parameters with the most significant correlations during both solar maximum and solar minimum. The dynamic pressure variation, however, shows higher correlation with ap than with Dst. This result is explained because ap depends on magnetospheric currents, more affected by the dynamic pressure. The distribution of index values per magnetic activity level increases substantially in the shocked period in relation to the whole period. For both indices the distributions are similar.