Identification of solar sources of major geomagnetic storms

We present the identification of solar coronal mass ejection (CME) sources for selected major geomagnetic storms (disturbance storm index-Dst⩽−100 nT) that occurred in October-November 2003. The CME data were obtained from the LASCO CME Catalog. We estimated time of flight of the CMEs from Sun to near-Earth space from their speed obtained from the linear fit, and identified the geoeffective ones. We analyzed the CMEs produced by the active region NOAA AR10486 from October 22 to November 4, during its passage across the visible solar disk. This huge sunspot region produced many X flares, the largest ones accompanied by intense >100 MeV SEP events and associated with full halo CMEs that mostly propagated in the western hemisphere, and caused strong geomagnetic storms. These results are in agreement with the idea that the fast and large CMEs propagating in a disturbed solar wind could accelerate energetic particles and intensify the magnetic storms.