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Titel |
Cluster and ACE observations of phase synchronization in intermittent magnetic field turbulence: a comparative study of shocked and unshocked solar wind |
VerfasserIn |
A. C.-L. Chian, R. A. Miranda |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
0992-7689
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Digitales Dokument |
URL |
Erschienen |
In: Annales Geophysicae ; 27, no. 4 ; Nr. 27, no. 4 (2009-04-14), S.1789-1801 |
Datensatznummer |
250016500
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Publikation (Nr.) |
copernicus.org/angeo-27-1789-2009.pdf |
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Zusammenfassung |
We apply two distinct nonlinear techniques, kurtosis and phase coherence
index, to analyze the modulus of interplanetary magnetic field data |B|
measured by Cluster and ACE spacecraft from 1 to 3 February 2002. High
degree of phase synchronization is found across a wide range of time scales,
from 1 s to 104 s, in the magnetic field fluctuations, both in the
shocked solar wind upstream of Earth's bow shock and in the unshocked ambient
solar wind at the L1 Lagrangian point. This is the first direct measurement
of phase coherence in the ambient solar wind turbulence. We show that phase
synchronization related to nonlinear multiscale interactions is the origin of
the departure from Gaussianity in the intermittent magnetic field turbulence.
In particular, we demonstrate that at small scales near the spectral break
the intermittency level of Cluster is lower than ACE, which may be a
signature of the reflected ions from the shock. |
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