HR: 11:55h
AN: SH32B-07    [Abstracts]
TI: Wave Number Spectra in the Solar Wind as Seen by CLUSTER Spacecraft
AU: * Narita, Y
EM: y.narita@tu-bs.de
AF: Institute of Geophysics and Extraterrestrial Physics, Technical University of Braunschweig, Mendelssohnstr. 3, Braunschweig, 38106, Germany
AU: Glassmeier, K
EM: kh.glassmeier@tu-bs.de
AF: Institute of Geophysics and Extraterrestrial Physics, Technical University of Braunschweig, Mendelssohnstr. 3, Braunschweig, 38106, Germany
AU: Goldstein, M L
EM: melvyn.l.goldstein@nasa.gov
AF: Geospace Physics Laboratory, Code 673, NASA Goddard Space Flight Center, Greenbelt, MD 20771, United States
AU: Treumann, R A
EM: treumann@issibern.ch
AF: Department of Geoscience, Geophysics Section, Ludwig-Maximilians-University Munich, Theresienstr. 41, Munich, 80333, Germany
AU: Gary, S
EM: pgary@lanl.gov
AF: Mail Stop D466, Los Alamos National Laboratory, Los Alamos, NM 87545, United States
AB: We present direct measurement of wave number spectra in the solar wind. We use magnetic field data obtained by the four CLUSTER spacecraft and apply the wave telescope method, which is particularly suited for multi- spacecraft data analyses, to determine the spectra of two-dimensional, Alfvénic, and compressible turbulence. The wave number spectra are characterized by the power law on intermediate scales (1000-10,000 km) and spectral breaks on smaller scales (100 km), reminiscent of turbulence. The wave number spectra also exhibit dominance of two-dimensional turbulence and only small contribution of compressible turbulence, which justifies the assertion of incompressible fluctuations in the solar wind and accounts for why the mean free paths of the cosmic rays are larger than predicted by the quasi-linear theory. On the other hand, the wave number spectra exhibit some different properties from that of the frequency spectra derived from the single spacecraft measurements. We discuss possible reasons and implications of the spectral differences between the wave number and frequency domain.
DE: 2149 MHD waves and turbulence (2752, 6050, 7836)
DE: 7863 Turbulence (4490)
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2007 Fall Meeting