Large Geomagnetic Storms and Their Relation with Coronal Mass Ejections and Interplanetary Magnetic Field

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 ≤ -150 nT to Dst ≥-3560nT observed during the period of 1997–2006 with coronal mass ejections, interplanetary shocks and disturbances in interplanetary magnetic field. We obtained scatter plots between magnitude of geomagnetic storms, magnitude of maximum depression in Dst with magnitude and peak values of Interplanetary Magnetic Field (IMF) components Bz and total IMF B. We have found that 90.00% geomagnetic storms are associated with halo and partial halo coronal mass ejections. We have found positive correlation between magnitude of geomagnetic storms and speed of associated coronal mass ejections. Further we have concluded that majority of the geomagnetic storms are associated with interplanetary shocks (90.00%). From the study of geomagnetic storms with disturbances in interplanetary magnetic field. We have determined positive co-relation between magnitude of maximum depression in Dst and peak values of total IMF B and southward component of interplanetary magnetic field Bz with correlation coefficient 0.64, 0.62 respectively. Positive correlation has been also found between magnitude of geomagnetic storms and magnitude of total interplanetary magnetic field B and southward component of IMFBz with correlation coefficient 0.58, 45 respectively.