Four-dimensional energy spectrum for space–time structure of plasma turbulence
A parametric model of the inertial-range energy spectrum is constructed for plasma turbulence in the four-dimensional wave vector and frequency domain. The model is based on that of the Eulerian wavenumber-frequency spectrum developed for describing fluid turbulence, and includes wave vector anisotr...
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2014-01-01
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| Series: | Nonlinear Processes in Geophysics |
| Online Access: | http://www.nonlin-processes-geophys.net/21/41/2014/npg-21-41-2014.pdf |
| Summary: | A parametric model of the inertial-range energy spectrum is constructed for
plasma turbulence in the four-dimensional wave vector and frequency domain.
The model is based on that of the Eulerian wavenumber-frequency spectrum
developed for describing fluid turbulence, and includes wave vector
anisotropies in the three-dimensional wave vector domain by approximating the
spectrum to a set of ellipses. The shape of the four-dimensional spectrum is
determined by the Doppler shift, the Doppler broadening, and anisotropy
coefficients. The model is applied to the magnetic energy spectrum in the
near-Earth solar wind measured by four Cluster spacecraft, and the set of the
spectral parameters are determined observationally. In this way, space–time
structure of plasma turbulence can be condensed into a small number of
parameters, which is suitable for evaluating the energy spectra in
observational and numerical studies on the quantitative basis. |
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| ISSN: | 1023-5809 1607-7946 |