We have studied intense geomagnetic storms magnitude (≤-100nT) observed between 2014 and 2017 with coronal mass ejections, hard X-ray solar flaresand disturbances in solar wind plasma parameters. We have observed that majority of the of intense geomagnetic storms, associated Hard X-Ray solar flares. It is observed that all the intense geomagnetic storms are Hard X-Ray solar flares of different categories. The association rates X-Class, M-Class, C-Class and B-Class X-ray solar flare are:X-Class -9.0%, M-Class-54.54%, C-Class -18.18%, B-Class -18.18% respectively. Intense geomagnetic storms which are associated with halo and partial halo coronal mass ejection (CMEs) are related to hard X-ray solar flares of different categories. It is also observed that these intense geomagnetic are associated with disturbances in solar wind plasma parameters. Positive correlation with correlation coefficient 0.71 has been found between the magnitude of intense geomagnetic storms and the peak value of associated disturbances in interplanetary magnetic fields (IMFB), 0.49between the magnitude of intense geomagnetic storms and the peak value of associated disturbances in southward component in interplanetary magnetic fields (IMF Bz), 0.79between the magnitude of intense geomagnetic storms and the peak value of associated disturbances in solar wind plasma pressure (SWP) . We have concluded that coronal mass ejections associated with hard X-ray solar flare are mainly responsible to cause intense geomagnetic storms.
Keywords:- Intense geomagnetic storms, Interplanetary magnetic fields, Southward component of interplanetary magnetic fields, solar wind plasma pressure, Coronal mass ejection (CMEs), HCMEs.
Varinder Pandey1, Saket Kumar2*, Dolly Ochani3, P. L. Verma4