HR: 0800h
AN: NG41B-0428    [Abstracts]
TI: Toward a Synthesis of Auroral Index Scaling Measurements
AU: * Watkins, N W
EM: nww@bas.ac.uk
AF: British Antarctic Survey, High Cross, Madingley Road, Cambridge, CB3 0ET United Kingdom
AU: Hnat, B
EM: hnat@astro.warwick.ac.uk
AF: Space and Astrophysics, University of Warwick, Coventry, CV4 7AL United Kingdom
AU: Chapman, S C
EM: sandrac@astro.warwick.ac.uk
AF: Space and Astrophysics, University of Warwick, Coventry, CV4 7AL United Kingdom
AU: Freeman, M P
EM: m.p.freeman@bas.ac.uk
AF: British Antarctic Survey, High Cross, Madingley Road, Cambridge, CB3 0ET United Kingdom
AU: Rowlands, G
EM: G.Rowlands@warwick.ac.uk
AF: Space and Astrophysics, University of Warwick, Coventry, CV4 7AL United Kingdom
AB: One route for study of magnetospheric energy release has been provided by scaling analysis of the Auroral Electrojet indices ($AE, AU, AL$). The scale invariance of aspects of the $AE$ index family was one-but not the sole-motivation to suggest self-organised critical ``avalanche'' scenarios of the magnetosphere. In that of Chapman $et al.$ [1998] the appearance of a characteristic scale in otherwise scale-free magnetospheric signals was identified with the properties of ``systemwide'' avalanches. It has long been recognised that the indices show a two-component nature, originally hypothesised to reflect solar wind-driven (DP2) and intrinsic (DP1) components in the ionospheric convection currents. Following the first avalanche scenarios, debate was sparked by one of the alternative possibilities, that the scale-invariant nature of the indices was due to Kolmogorov or Kraichnan scaling in solar wind MHD turbulence. We will present an up-to date review of subsequent work on scaling by the Warwick and BAS groups. We will also discuss the inter-relationships of our results with those of other workers.
DE: 7863 Turbulence
DE: 2784 Solar wind/magnetosphere interactions
DE: 2788 Storms and substorms
DE: 3200 MATHEMATICAL GEOPHYSICS (New field)
SC: Nonlinear Geophysics [NG]
MN: 2004 AGU Fall Meeting