  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.

Space Physics