Solar flare and geomagnetic activity relations

Abstract

Two x-ray solar flare parameters (number of flares and peak flux) are compared to geomagnetic and space weather activity indices. The first solar flare parameter, X-ray solar flare number (SFN), is the total number of solar flares observed in a given month. The second one is the monthly maximum of X-ray solar flare peak fluxes (SFP). In order to compare these two parameters, both of them are cross-correlated with some other indices of geomagnetic activity (aa, Dst, and AE indices) and space weather (maximum coronal mass ejection speed index and solar wind speed). Maximum correlation was found (∼0.63) between both flare time series (SFN and SFP) and maximum coronal mass ejection speed index with no lag. Our results show that X-ray solar flare peak flux better describes those geomagnetic and space weather activity indices than X-ray solar flare numbers. This is mostly because of high time delays between flare numbers and studied indices.