Analysis of Solar Wind Parameters Related to Geomagnetic Storms Using Detrended Fluctuation Analysis (DFA) Method
Miftahul Husna, Dhani Herdiwijaya, and Chandra Alif Fernanda

Astronomy Division, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, Ganesha 10 Bandung, Indonesia 40132
Email: dhani.herdiwijaya[at]itb.ac.id

Abstract

The propagation of the Solar Wind (SW) by carrying plasma and magnetic fields that reach the Earth and potential to cause impacts on the Earth^s environment. SW triggers the occurrence of disturbances in the Earth^s magnetic field on a global scale known as geomagnetic storms. We present a study of the nature and general patterns of fluctuations in the SW^s parameters as a function of time. We choose samples of strong class geomagnetic storm (SGS) events for the Sun^s 20th to 21st cycles (October 1964 - September 1986). Within that range, there are 120 strong to extreme-class geomagnetic storm events. We analyzed the parameters of the SW^s fluctuating using the Detrended Fluctuation Analysis (DFA) method resulting in an alpha component (Hurst exponent generalized). The range of alpha values on the SGS event sample for six days before the peak of 0.02<alpha<5.62 (dominated by persistent processes), on the peak day of 0<alpha<5.6 (dominated by nonstationary processes), and six days after the peak of 0<alpha<3.23 (dominated by persistent processes). Parameters with persistent process types are relatively easier to use as one of the tools that can be used in prediction. Unlike the peak of a storm, the process is predominantly nonstationary which changes with time, difficult to use in predictions. However, a longer data range is needed to see a complete pattern in SW parameters because geomagnetic storms are complex systems that are difficult to predict. Therefore, an examination is required on the next cycle of the Sun.

Keywords: Solar wind, Strong Geomagnetic Storm (SGS), Detrended Fluctuation Analysis (DFA), Hurst exponent, process: persistent- anti-persistent- nonstationary- and stationary

Topic: EARTH, ATMOSPHERIC, AND SPACE SCIENCE