HR: 1340h
AN: SH33A-1075    [Abstracts]
TI: Multi-Spacecraft observations of nonlinear spatial correlation properties of solar wind fluctuations- Mutual Information estimates and solar cycle dependence
AU: * Wicks, R T
EM: R.Wicks@warwick.ac.uk
AF: Centre for Fusion, Space and Astrophysics, Physics Dept., Univ. of Warwick, Coventry, CV4 7AL, United Kingdom
AU: Chapman, S C
EM: S.C.Chapman@warwick.ac.uk
AF: Centre for Fusion, Space and Astrophysics, Physics Dept., Univ. of Warwick, Coventry, CV4 7AL, United Kingdom
AU: Dendy, R O
EM: richard.dendy@ukaea.org.uk
AF: Culham Science Centre, Euratom/UKAEA Fusion, Culham, Abingdon, OX14 3DB, United Kingdom
AB: The WIND and ACE spacecraft spend extended (from weeks to years) intervals in the solar wind, potentially providing observations of the spatial correlation properties of both coherent structures and evolving turbulence. We estimate the correlation length scale in the solar wind using a nonlinear measure- mutual information- and linear cross correlation, the latter to facilitate comparison with previous work. We consider quantities such as Elsässer variables expected to characterize Alfvénic turbulent fluctuations alongside "non cascade" quantities such as the magnetic field magnitude and the proton density. We find that the magnetic field magnitude and the proton density have different correlation length scales to each other. We also consider variation with the solar cycle; this strongly modulates the correlation lenghtscale seen in ρ and |B|, but not that seen in the Elsässer variables for example. Our quantitative estimates of correlation lengthscales relate directly to the phenomenology of the solar wind, either in the context of turbulence, or that of propagating structures of coronal origin.
DE: 2159 Plasma waves and turbulence
DE: 2164 Solar wind plasma
DE: 2169 Solar wind sources
DE: 3270 Time series analysis (1872, 4277, 4475)
DE: 7536 Solar activity cycle (2162)
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2007 Fall Meeting