Dynamical information flow within the magnetosphere-ionosphere system during magnetic storms

TL;DR

This study applies transfer entropy to analyze the dynamic information flow between the magnetosphere and ionosphere during geomagnetic storms, aiming to resolve controversies and better understand storm-time particle energization.

Contribution

It adapts the transfer entropy method to geomagnetic storm data, enabling analysis of local, non-stationary information flow and its transition during storm phases.

Findings

Characterizes information flow dynamics during storms

Reveals transition patterns from quiet to disturbed states

Provides insights into magnetosphere-ionosphere coupling

Abstract

The direct role of successive intense magnetospheric substorms in injecting/energizing particles into the storm-time ring current is still debated and controversial. Whereas in the recent past it has been observed the absence of a net information flow between magnetic storms and substorms, previous in-situ satellite observations have evidenced that ionospheric-origin ions dominate the population of the ring current during the main phase of geomagnetic storms. As a matter of fact, the controversy arises mainly by the use of sophisticated data-driven techniques somewhat contradicting in-situ measurements. In this framework, the main aim of this work is to attempt an adaption of the powerful information-theoretic approach, i.e., the transfer entropy, in a consistent way with physics modeling and observations and to explore the possible motivations behind the underlying contradictions that emerge when these techniques are used. Our idea is to characterize the dynamics of the information flow within the magnetosphere-ionosphere system using a database of geomagnetic storms instead of considering a long time series of geomagnetic indices. This allows us to consider local non-stationary features of the information flow and, most importantly, to follow the transition from quiet to disturbed periods and vice-versa.