Dependence of the cross polar cap potential saturation on the type of solar wind streams

Abstract

We compare of the cross polar cap potential (CPCP) saturation during magnetic storms induced by various types of the solar wind drivers. By using the model of Siscoe-Hill \citep{Hilletal1976,Siscoeetal2002a,Siscoeetal2002b,Siscoeetal2004,Siscoe2011} we evaluate criteria of the CPCP saturation during the main phases of 257 magnetic storms ($Dst_{min} \le -50$ nT) induced by the following types of the solar wind streams: magnetic clouds (MC), Ejecta, the compress region Sheath before MC ($Sh_{MC}$) and before Ejecta ($Sh_{E}$), corotating interaction regions (CIR) and indeterminate type (IND). Our analysis shows that occurrence rate of the CPCP saturation is higher for storms induced by ICME ($13.2%$) than for storms driven by CIR ($3.5%$) or by IND ($3.5%$).The CPCP saturation was obtained more often for storms initiated by MC ($25%$) than by Ejecta ($2.9%$); it was obtained for $8.6%$ of magnetic storms induced by sum of MC and Ejecta, and for $21.5%$ magnetic storms induced by Sheath before them (sum of $Sh_{MC}$ and $Sh_{E}$). These results allow us to conclude that occurrence rate of the CPCP saturation at the main phase of magnetic storms depends on the type of the solar wind stream.