Analysis of the October 3-7 2000 and April 15-24 2002 Geomagnetic Storms with the WINDMI model

A computationally optimized model of the magnetosphere-ionosphere system called WINDMI is used to analyze two large geomagnetic storm events, Oct 3-7 2000 and Apr 15-24 2002. These two storms share common features such as the passage of a magnetic cloud, shock events and the occurrence of periodic substorms. The input into the model is a driving voltage derived from the solar wind dynamic pressure and the interplanetary magnetic field measured by the ACE satellite. Two key outputs of the model are (1) the nightside field aligned region 1 current that closes in the auroral ionosphere giving the AL index from the westward electroject and (2) the total energy in the ring current plasma driven by the plasma sheet with losses from the charge exchange of the fast ions which is then converted to the ground based Dst signal through the Dessler-Parker-Schopke relationship. The model parameters are optimized using a genetic algorithm to search for solutions that simultaneously have least mean square fit to the AL and Dst indices and also possess substorms of period 2-4 hours. Good results have been obtained for both geomagnetic storm periods.