Abstract
An information-theoretic approach for detecting causality and information transfer is used to identify interactions of solar activity and interplanetary medium conditions with the Earth’s magnetosphere–ionosphere systems. A causal information transfer from the solar wind parameters to geomagnetic indices is detected. The vertical component of the interplanetary magnetic field () influences the auroral electrojet (AE) index with an information transfer delay of 10 min and the geomagnetic disturbances at mid-latitudes measured by the symmetric field in the H component (SYM-H) index with a delay of about 30 min. Using a properly conditioned causality measure, no causal link between AE and SYM-H, or between magnetospheric substorms and magnetic storms can be detected. The observed causal relations can be described as linear time-delayed information transfer.
Highlights
One of the fundamental problems in space weather studies is the way the Earth’s magnetosphere–ionosphere system responds to the solar activity and to interplanetary medium conditions [1]
In order to find the causality directions as well as the presence of any information transfer delay between the solar wind and the geomagnetic indices, we calculate conditional mutual information among such time series using CMI defined in Equation (13), computed using the equiquantal binning estimator [34]
Note that red lines and error bars, respectively, show the mean and ±2 standard deviations (SD) of the corresponding CMI obtained from a set of 100 circular time-shifted surrogates
Summary
One of the fundamental problems in space weather studies is the way the Earth’s magnetosphere–ionosphere system responds to the solar activity and to interplanetary medium conditions [1]. A number of information-theoretic measures have been proposed to uncover the underlying dynamics of interactions between the magnetosphere system and solar wind as well as the purely internal processes in this system [16,17,18,19,20,21,22] It has been proposed in [17] that during small geomagnetic disturbances a dominant flow of information exists from the geomagnetic activity indices AL as a substorm index into the symmetric horizontal component disturbances SYM-H as a magnetic storm index, using the bivariate transfer entropy [23]. This assertion is supported using linear versions of three independent causality detection methods
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
