Dynamics of the Earth’s magnetopause’s subsolar location during solar cycle 24 in relation to the phases of geomagnetic storms of CME origin

This article analyses the response of the subsolar position (Ro) of the Earth’s magnetopause to geo-effective ICME storms in solar cycle 24, ranging from minor to extreme intensity, based on the model developed by Shue et al. (1998) and 1-minute OMNI data. The study combines a phase analysis of representative storms with an analysis of the influence of Ro variability on solar wind parameters, without phase distinction (correlations, time lags, Granger causality, and adjustments). The results show that the dynamics of Ro are driven almost exclusively by Pd in the minor and moderate storms studied, while a synergistic shift appears in strong and extreme storms, where magnetic reconnection or even magnetopause erosion becomes decisive. The crossing of the magnetopause at the subsolar point of the geosynchronous orbit (<6.6 Re) is a signature of the main phase of the storm on 22 June 2015 (strong) and the initial and main phase of the storm on 17 March 2015 (extreme). The autocorrelation correction confirms the robustness of the high correlations observed. The relationships between Ro and Pd remain linear except for the extreme event, while Bz requires polynomial adjustments in most of the events studied. Variations in Pd and N precede those in Ro by 1 min to 3 min and significantly influence those in Ro, with a maximum effect at lag = 0 min in almost all events. The predominant response of Ro to the magnetic constraint imposed by B is delayed, with lag varying from 30 min to 7 min depending on the event, except in the extreme case where lag = 0 min, controlled by the structure of the magnetosphere, and Bz plays a secondary role except in the extreme case where it contributes to magnetic reconnection and magnetopause erosion.