Modeling and comparison of two geomagnetic storms

Abstract

This paper describes the investigation and comparison of two consecutive geomagnetic storms of Solar Cycle 24. The first storm is moderate (Dst = −50 nT) and occurred on 22 April 2017, while the second storm is intense (Dst = −125 nT) and occurred on 28 May 2017. These storms are compared on the basis of solar wind parameters (Bz, E, P, N, v, and T) and zonal geomagnetic indices (Dst, ap, and AE). Mathematical analysis is performed with a data set of 9 variables obtained from NASA's observations. Descriptive statistics, which demonstrates the power of binary relationships with a covariance matrix; hierarchical clustering with a dendrogram; and factor analysis pointing to three separate eigenvectors are the primary tools of our study analysis. From the results, linear models are established from the cause-effect relationship of zonal geomagnetic indices with solar wind parameters governed by the causality principle. Finally, nonlinear models are also established with solar wind pressure (P), proton density (N), and ap index. In all analyses, the causality principle is obeyed rigidly and the mathematical models are discussed in terms of the cause-effect relationship.