Complexity measures of geomagnetic indices in the last two solar cycles

The SYM-H and AE geomagnetic indices can be considered as proxies of the response Earth’s magnetosphere ionosphere to solar magnetic activity. They indirectly monitor some electric current systems which flow in whose dynamics are directly or related Sun–Earth interaction. Consequently, their temporal changes reflect processes occurring near-Earth space, contribute differently overall magnetosphere–ionosphere dynamics. aim this work is characterize nature these two by following a complex system approach applying novel formalism, e.g., EMD-based dominant amplitude multifractal formalism (EMD-DAMF). A set complexity measures, i.e., Hurst exponent ( H ), singularity width ? ? ) spectrum f evaluated for both analyzing data recorded during last cycles. One most significant findings study absence relevant differences between cycles terms measures indices, suggesting that only occurrence frequency storms substorms affect widths indices. Moreover, while index do not show dependence on activity, shows reduction its features storms, manifesting more persistent behavior moving from (mono)fractal-like multifractal-like when passing quiet disturbed periods. Finally, our consistent with previous works forecast horizon activity well relation high-latitude low-latitude magnetosphere, thus confirming importance providing higher resolution correctly dealing several Space Weather phenomena. • used AE. Only measures. has an intermittent character magnetotail change Complexity crucial modeling purposes