Measuring Information Coupling between the Solar Wind and the Magnetosphere–Ionosphere System

Mirko Stumpo,Virgilio Quattrociocchi,Giuseppe Consolini,Tommaso Alberti

doi:10.3390/e22030276

Abstract

The interaction between the solar wind and the Earth’s magnetosphere–ionosphere system is very complex, being essentially the result of the interplay between an external driver, the solar wind, and internal processes to the magnetosphere–ionosphere system. In this framework, modelling the Earth’s magnetosphere–ionosphere response to the changes of the solar wind conditions requires a correct identification of the causality relations between the different parameters/quantities used to monitor this coupling. Nowadays, in the framework of complex dynamical systems, both linear statistical tools and Granger causality models drastically fail to detect causal relationships between time series. Conversely, information theory-based concepts can provide powerful model-free statistical quantities capable of disentangling the complex nature of the causal relationships. In this work, we discuss how to deal with the problem of measuring causal information in the solar wind–magnetosphere–ionosphere system. We show that a time delay of about 30–60 min is found between solar wind and magnetospheric and ionospheric overall dynamics as monitored by geomagnetic indices, with a great information transfer observed between the z component of the interplanetary magnetic field and geomagnetic indices, while a lower transfer is found when other solar wind parameters are considered. This suggests that the best candidate for modelling the geomagnetic response to solar wind changes is the interplanetary magnetic field component . A discussion of the relevance of our results in the framework of Space Weather is also provided.

Highlights

IntroductionIn the past decades a large amount of work has been done to provide new insights within the Space Weather discipline, e.g., the investigation, characterization and forecasting of physical processes operating in the near-Earth environment and their relation with the solar activity [1]
The response of the Earth’s magnetosphere–ionosphere system to the changes of solar wind and interplanetary medium conditions is the central issue of the studies in the framework of SpaceWeather
This suggests that the whole information content of the solar wind variability is not sufficient for a correct characterization and forecasting of the magnetosphere–ionosphere system; this aspect is clearly evidenced by the difficulty of reproducing the short timescale dynamics of geomagnetic indices only using solar wind plasma parameters [15]

Summary

Introduction

In the past decades a large amount of work has been done to provide new insights within the Space Weather discipline, e.g., the investigation, characterization and forecasting of physical processes operating in the near-Earth environment and their relation with the solar activity [1] These include large-scale induced currents [2,3], geomagnetic storms and substorms [4], solar energetic particle events [5,6,7], and so on [8]. All these phenomena have a common driver which is the solar activity evolving on both temporal and spatial scales across the heliosphere, reaching the Earth’s boundary regions and interacting with the near-Earth electromagnetic environment. This suggests that the whole information content of the solar wind variability is not sufficient for a correct characterization and forecasting of the magnetosphere–ionosphere system; this aspect is clearly evidenced by the difficulty of reproducing the short timescale dynamics of geomagnetic indices only using solar wind plasma parameters [15]

Methods

Results

Conclusion