Coronal Mass Ejections, Storms in Solar Wind Plasma Parameters and Mag- netic Clouds In Relation With Intense Geomagnetic Storms

Coronal mass ejections are most energetic solar events that eject huge amount of mass and magnetic fields into the heliosphere and are widely recognized as being responsible to generate storms in solar wind plasma parameters and geomagnetic storms in the magnetosphere of the earth. We have studied geomagnetic storms Dst ≤ - 100nT observed during the period of 1997-2006, with halo and partial halo coronal mass ejections associated with X-ray solar flares, interplanetary shocks, and magnetic clouds, which are interplanetary manifestations of coronal mass ejections. We have found that 84.93% geomagnetic storms are associated with halo and partial halo coronal mass ejections. The association rate of geomagnetic storms with halo and partial halo coronal mass ejections are found 74.91% and 25.81% respectively. The halo and partial halo coronal mass ejections, which are related to geomagnetic storms, majority of them are associated with X-ray solar flares (90.00%). Further we have concluded that majority of the geomagnetic storms are associated with forward shocks (88.16%) and some of them are related to magnetic clouds (50.74%) also. From the study of geomagnetic storms with storms in solar wind plasma parameters, we have determined positive corelation between magnitude of geomagnetic storms and peak values of associated storms in solar wind plasma parameters with co-relation co-efficient .32 between magnitude of geomagnetic storms and peak values of associated storms in solar wind plasma temperature, .48 between magnitude of geomagnetic storms and peak values of associated storms in solar wind plasma velocity , .68 between magnitude of geomagnetic storms and peak values of associated storms in interplanetary magnetic field. We have concluded that halo and partial halo coronal mass ejections associated X-ray solar flares and related to forward shocks, magnetic clouds or both are very much effective in producing intense geomagnetic storms.