Solar origins of intense geomagnetic storms in 2002 as seen by the CORONAS-F satellite

Abstract We analyze solar origins of intense geomagnetic perturbations recorded during 2002. All of them were related to coronal mass ejections (CMEs). The initiation of CMEs was documented using the SPIRIT instrument (SPectrohelIographic Soft X-Ray Imaging Telescope) onboard the CORONAS-F satellite. Monochromatic full Sun images taken in the Mg XII doublet at 8.418 and 8.423 A showed the appearance of free energy release sites at altitudes up to 0.4 solar radii. CMEs were initiated at these sites and propagated in interplanetary space under appropriate local conditions including the geometry of the magnetic fields.