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| Titel |
Excitation of kinetic Alfvén turbulence by MHD waves and energization of space plasmas |
| VerfasserIn |
Y. Voitenko, M. Goossens |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1023-5809
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| Digitales Dokument |
URL |
| Erschienen |
In: Nonlinear Processes in Geophysics ; 11, no. 5/6 ; Nr. 11, no. 5/6 (2004-11-16), S.535-543 |
| Datensatznummer |
250008983
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| Publikation (Nr.) |
 copernicus.org/npg-11-535-2004.pdf |
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| Zusammenfassung |
| There is abundant observational evidence that the energization of
plasma particles in space is correlated with an enhanced activity
of large-scale MHD waves. Since these waves cannot interact with
particles, we need to find ways for these MHD waves to transport
energy in the dissipation range formed by small-scale or
high-frequency waves, which are able to interact with particles.
In this paper we consider the dissipation range formed by the
kinetic Alfvén waves (KAWs) which are very short- wavelengths
across the magnetic field irrespectively of their frequency. We
study a nonlocal nonlinear mechanism for the excitation of KAWs by
MHD waves via resonant decay AW(FW)→KAW1+KAW2, where the MHD wave can be either an Alfvén
wave (AW), or a fast magneto-acoustic wave (FW). The resonant
decay thus provides a non-local energy transport from large scales
directly in the dissipation range. The decay is efficient at low
amplitudes of the magnetic field in the MHD waves, B/B0~10-2. In turn, KAWs are very efficient in the energy exchange
with plasma particles, providing plasma heating and acceleration
in a variety of space plasmas. An anisotropic energy deposition in
the field-aligned degree of freedom for the electrons, and in the
cross-field degrees of freedom for the ions, is typical for KAWs.
A few relevant examples are discussed concerning nonlinear
excitation of KAWs by the MHD wave flux and consequent plasma
energization in the solar corona and terrestrial magnetosphere. |
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