HR: 1340h
AN: NG23A-1192    [Abstracts]
TI: Correlation Dimension Analysis Applied to a Magnetotail Coupled-Map Lattice Model
AU: * Bates, I
EM: i.bates@sheffield.ac.uk
AF: Automatic Control and Systems Engineering Department, University of Sheffield, Mappin Street, Sheffield, S1 3JD United Kingdom
AU: Gedalin, M
EM: gedalin@bgumail.bgu.ac.il
AF: Department of Physics, Ben-Gurion University, P.O.Box 653, Beer-Sheva, 84105 Israel
AU: Suri, V
AF: Automatic Control and Systems Engineering Department, University of Sheffield, Mappin Street, Sheffield, S1 3JD United Kingdom
AB: It has been suggested that slowly driven dynamical systems, with many degrees of freedom, self-organise into a critical state, with avalanches of all sizes obeying power law characteristics. Various recent observations and numerical simulations suggest that the Earth's magnetotail system, a highly complex system, could exist in a near-critical configuration. Although no experiment exists to prove entirely that a system is self-organised critical (SOC), several pieces of evidence can be collected to support the idea, e.g.\ exhibition of power-law scaling in distribution functions. An additional tool that can be used to reveal information from an observed time-series is correlation dimension analysis. The goal of a correlation dimension analysis is to extract, from a highly complex system with many degrees of freedom, the dimension of an underlying chaotic attractor. The existence of such a dimension may be used as evidence to argue whether a system is in a SOC state or otherwise. The numerical simulation used in this work, a magnetic field model of the magnetotail current sheet, has been developed by, amongst others, {Takalo, Timonen et al., (1999)}. It is in the form of a Coupled-Map Lattice (CML) and is based on the MHD diffusion equation and is continuously driven by solar wind \emph{vBs} data. It has been shown by {Takalo, Timonen et al., (1999)} that the model exhibits perturbations (avalanches) with power-law scalings in their distributions of duration and size. Such distributions may indicate SOC behaviour. This paper presents the results of a correlation dimension analysis of the numerical outputs of the CML model and discusses the implications.
UR: http://www.acse.shef.ac.uk/$\sim$bates/research/?file=abstracts
DE: 7800 SPACE PLASMA PHYSICS
DE: 7839 Nonlinear phenomena
DE: 7843 Numerical simulation studies
DE: 2744 Magnetotail
DE: 3200 MATHEMATICAL GEOPHYSICS (New field)
SC: Nonlinear Geophysics [NG]
MN: 2004 AGU Fall Meeting