HR: 13:55h
AN: SH33B-02    [Abstracts]
TI: Measurements of the wavevector anisotropy of solar wind turbulence
AU: * Horbury, T
EM: t.horbury@imperial.ac.uk
AF: Imperial College London, Prince Consort Road, London, SW7 2BW, United Kingdom
AU: Forman, M
EM: maforman@notes.cc.sunysb.edu
AF: State University of New York at Stony Brook, Department of Physics and Astronomy, Stony Brook, NY 11794-3800, United States
AU: Oughton, S
EM: seano@waikato.ac.nz
AF: University of Waikato, Department of Mathematics Private Bag 3105, Hamilton, 3240, New Zealand
AB: We present a new, wavelet-based analysis of solar wind magnetic field data which makes it possible to determine the wavevector anisotropy of the fluctuations with respect to the local mean field direction. We demonstrate, consistent with published work, that the fluctuations within the inertial range are dominated by power in wavevectors at large angles to the field (so-called "2D"). In an important new result, we also show how the spectral index, γ, varies with the angle between the radial (measurement) and mean field directions. At most angles γ ≈ 5/3 , however this smoothly transitions to 2 for small angles, i.e., those associated with fluctuations with wavevectors nearly parallel to the field ("slab"). We also demonstrate significant deviations from a simple slab and 2D model, perhaps due to power at intermediate angles or finite wave propagation speeds. Finally, we discuss the anisotropy of the field magnitude spectrum, a proxy for density variations, and how this relates to the anisotropy in the field components.
DE: 7863 Turbulence (4490)
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2007 Fall Meeting