Study of Large Geomagnetic Storms (GMSs) and Space Weather Impacts

Dr. Rahul Shrivastava and Dr. Subhas Chand Dubey

Aim of this statistical is to define the various characteristics of large geomagnetic storms (GMSs) associated with Dst decreases of more than 100 nT, observed during solar cycle 23. Out of the selected 90 large GMSs, 51 are sudden commencement type and rest 39 is gradual commencement type Long-term and storm time variation as well as seasonal and solar cycle dependence of above mentioned GMSs have been analysed. The study of solar cycle 23 is remarkable for occurrence of large GMSs during its declining phase. Various types of geomagnetic disturbances and their possible solar and interplanetary causes are explained in this work that provides a better aspect to understand the space-weather phenomenon. Several solar-terrestrial inter-connection mechanism and new results have been discussed in the present study. The severe GMSs have also been discussed that are very harmful to us, and they affect our communication system, power system.