Authors : Ibrahim Jafaru; Bishir Usman

Volume/Issue : Volume 7 - 2022, Issue 6 - June

Google Scholar : https://bit.ly/3IIfn9N

Scribd : https://bit.ly/3uOIO5I

DOI : https://doi.org/10.5281/zenodo.6834350

Abstract : The present work focuses on finding the relation between strong, moderate and small geomagnetic storms based on disturbed storm time index and the orientation of interplanetary magnetic field. In this work the data selected is from year 2015 to 2018 and classification of the geomagnetic storms is done on the basis of Dst (ring current) as intense geomagnetic storms (Dst<-100 nT), moderate geomagnetic storms (-99nT ≤ Dst≤ -80 nT) and small geomagnetic storms (-79nT ≤Dst ≤ -60 nT).The Dst index datawas obtained from the World Data Centre for Geomagnetism, WDC-Kyoto. The solar parameters; solar proton density (Np), solar proton speed (Vp), solar proton temperature(Tp) and vertical component of Interplanetary Magnetic Field (IMF_z) of the same duration are taken fromAdvance Composition Explorer (ACE) spacecraft, as given by the ACE Science Centre. During this period 9 intense geomagnetic events, 11 moderate geomagnetic storms and 5 small geomagnetic activities are observed.From these data sets a total of 10 events were selected for the study, out of which 5 are intense geomagnetic storms, 3 are moderate geomagnetic storms and 2 are small geomagnetic storms. In case of intense geomagnetic storms disturbed storm index (Dst) lag behind interplanetary magnetic field (IMF) by 10 hours, for moderate geomagnetic storms disturbed storm index (Dst) lag behind interplanetary magnetic field (IMF) by 4hours and disturbed storm index(Dst) lag behind interplanetary magnetic field (IMF) by 16hours in small geomagnetic storms. ThusDst index is following the southward orientation of vertical component of interplanetary magnetic field as consequential of varied solar parameters.

Keywords : Solar Proton Density, Solar proton Temperature, Solar proton speed, IMF and Dst index.