| Full text | |
| Author(s): |
Raphaldini, Breno
;
Ciro, David
;
Medeiros, Everton S.
;
Massaroppe, Lucas
;
Trindade, Ricardo I. F.
Total Authors: 5
|
| Document type: | Journal article |
| Source: | PHYSICAL REVIEW E; v. 101, n. 2, p. 8-pg., 2020-02-12. |
| Abstract | |
The geomagnetic field's dipole undergoes polarity reversals in irregular time intervals. Particularly long periods without reversals (of the order of 10(7) yr), called superchrons, have occurred at least three times in the Phanerozoic (since 541 million years ago). We provide observational evidence for high non-Gaussianity in the vicinity of a transition to and from a geomagnetic superchron, consisting of a sharp increase in high-order moments (skewness and kurtosis) of the dipole's distribution. Such an increase in the moments is a universal feature of crisis-induced intermittency in low-dimensional dynamical systems undergoing global bifurcations. This implies a temporal variation of the underlying parameters of the physical system. Through a low-dimensional system that models the geomagnetic reversals, we show that the increase in the high-order moments during transitions to geomagnetic superchrons is caused by the progressive destruction of global periodic orbits exhibiting both polarities as the system approaches a merging bifurcation. We argue that the non-Gaussianity in this system is caused by the redistribution of the attractor around local cycles as global ones are destroyed. (AU) | |
| FAPESP's process: | 13/26598-0 - Fractal Boundaries between chaos and periodicity in the parameters space. |
| Grantee: | Everton Santos Medeiros |
| Support Opportunities: | Scholarships in Brazil - Post-Doctoral |
| FAPESP's process: | 15/50686-1 - Paleo-constraints on monsoon evolution and dynamics |
| Grantee: | Pedro Leite da Silva Dias |
| Support Opportunities: | Research Projects - Thematic Grants |
| FAPESP's process: | 18/03211-6 - Non linear dynamics |
| Grantee: | Iberê Luiz Caldas |
| Support Opportunities: | Research Projects - Thematic Grants |
| FAPESP's process: | 17/23417-5 - Paleoclimatic variability of South Atlantic Convergence Zone and processes in the Atlantic and Pacific Oceans: Last Glacial, Middle Holocene and Last Millennium |
| Grantee: | Breno Raphaldini Ferreira da Silva |
| Support Opportunities: | Scholarships in Brazil - Post-Doctoral |