Statistical study of equatorial geomagnetic crochets

Abstract

This study present the statistical investigation of equatorial geomagnetic crochets due to strong solar flare of class M to X. Our analysis utilized data from eight magnetometer stations provided by MAGnetic Data Acquisition System network (MAGDAS) at different longitudes sector during period from January 2008 to March 2015. We have considered 52 cases of solar flare events. Based on our analysis, 65% of the studied solar flares show no effect on geomagnetic variation with most of it from class M8, M9 and X1. The absence of solar flare effect might due to the influence of coronal mass ejection (CME) on the observation data or due to the station's location is at nighttime. The other 35% shows geomagnetic crochets to the magnetic data variation where majority are mix effect dominated by positive crochets. Apart from that, we also found an interesting solar flare effect where negative geomagnetic crochets were detected from all equatorial magnetometer data. The unique effect is due to X-class solar flare on 9th August 2011. Further investigation using extended latitudinal and longitudinal magnetometer is recommended to observe the whole picture of the solar flare effect to global ionospheric current.