Nonlinear Interdependence features in Solar wind parameters influencing
geomagnetic activity during geomagnetic storm
Abstract
In this study, we examine the nonlinear interdependence between the
parameters of the solar wind influencing geomagnetic activity (proton
density and solar wind dynamic pressure, IMF Bz and solar wind dynamic
pressure) and geomagnetic activity (AE and SYM-H) during pre-storm,
storm and post-storm of intense, major, moderate and minor geomagnetic
storms. Nonlinear analytical tools comprising cross recurrence plot
(CRP) and Recurrence Rate (RR) was used to capture the features of
nonlinear interdependence in the time series data of the solar wind
parameter (solar wind dynamic pressure, IMF Bz and proton density) and
geomagnetic indices (AE and SYM-H). The pearson correlation coefficient
was also used to reveal the features of linear dependence between the
parameters of the solar wind during the different categories of
geomagnetic storms. Our result shows that during the storm, the CRPs of
the solar wind parameters investigated pictured a strong deterministic
structure of CRP which is an indication of strong interdependence. In
particular, the results of our analysis showed that the solar wind
dynamic pressure and proton density depicted very strong interdependence
features. On the other hand, during pre-storm and post-storm, the CRP of
solar wind dynamic pressure in relation to IMF Bz and proton density
pictured a rare deterministic structure signifying weak interdependence.
Furthermore, the values of RR were very high (an indication of strong
interdependence between the parameters of the solar wind) during the
storm while at pre-storm and post-storm, the values of RR declined
significantly in most of the periods which further strengthened the
evidence of weak interdependence in the parameters of solar wind. The
CRP and RR of the geomagnetic indices (AE and SYM-H) reveals no
significant difference between pre-storm, storm and post-storm of the
different categories of geomagnetic storms. However, strong
interdependence between the geomagnetic indices were observed in most of
the periods investigated. Finally, the pearson correlation coefficient
reveals high values of linear dependence between the solar wind
parameters without any significant difference between pre-storm, storm
and post-storm periods during intense, major, moderate and minor
geomagnetic storms.