ANGEO Annales Geophysicae ANGEO Ann. Geophys. 1432-0576 Copernicus Publications Göttingen, Germany 10.5194/angeo-21-1975-2003 Geometrical characteristics of magnetospheric energetic ion time series: evidence for low dimensional chaos Pavlos G. P. 1 Athanasiu M. A. 1 Rigas A. G. 1 Sarafopoulos D. V. 1 Sarris E. T. 1 Department of Electrical and Computer Engineering, Demokritos Univercity of Thrace, 67100 Xanthi, Greece 30 09 2003 21 9 1975 1993 Copyright: © 2003 G. P. Pavlos et al. 2003 This work is licensed under the Creative Commons Attribution 3.0 Unported License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/3.0/ This article is available from https://angeo.copernicus.org/articles/21/1975/2003/angeo-21-1975-2003.html The full text article is available as a PDF file from https://angeo.copernicus.org/articles/21/1975/2003/angeo-21-1975-2003.pdf

In the first part of the paper we study the geometrical characteristics of the magnetospheric ions’ time series in the reconstructed phase space by using the SVD extended chaotic analysis, and we test the strong null hypothesis supposing that the ions’ time series is caused by a linear stochastic process perturbed by a static nonlinear distortion. The SVD reconstructed spectrum of the ions’ signal reveals a strong component of high dimensional, external coloured noise, as well as an internal low dimensional nonlinear deterministic component. Also, the stochastic Lorenz system produced by coloured noise perturbation of the deterministic Lorenz system was used as an archetype model in comparison with the dynamics of the magnetrospheric ions.<br><br><b>Key words. </b>Magnetospheric physics (energetic particles) – Radio science (nonlinear phenomena)