Berlin 2005 – wissenschaftliches Programm

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EP: Extraterrestrische Physik

EP 1: Magnetosph
äre und Ionosph
äre

EP 1.6: Vortrag

Freitag, 4. März 2005, 11:15–11:30, TU BH349

From normal state to magnetic storms in terms of fractal dynamics — •Georgios Balasis¹, Panayiotis Kapiris², and Konstantinos Eftaxias² — ¹GeoForschungsZentrum Potsdam, Telegrafenberg, D-14473, Potsdam, Germany — ²Faculty of Physics, University of Athens, Panepistimiopolis, Zografos, 15784 Athens, Greece

By monitoring the temporal evolution of fractal spectral characteristics in D_st time series we find distinctive symptoms indicating the approach to a major magnetic storm: (i) Emergence of long-range correlations. (ii) Gradual increase of the spatial correlation. (iii) Decrease of the fractal dimension with time, indicating strong anisotropy in substorm activity. (iv) Strong anti-persistent behavior in the first epoch of the precursory geomagnetic activity. (v) Decrease of the anti-persistent behavior with time. (vi) Emergence of persistency in the “tail” of the precursory epoch. (vii) Predominance of large geomagnetic events with time coupled with the appearance of higher frequencies in the spectrum. (viii) Significant acceleration of the energy release, i.e., increase of the susceptibility of the system with time. The question whether the evolution towards global instability is inevitable after the appearance of distinctive symptoms is discussed. The results could be studied in terms of “Intermittent Criticality”. The analysis suggests that the continuous scale invariance is partially broken into a discrete scale invariance symmetry.