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| Titel |
Solar wind density spectra around the ion spectral break |
| VerfasserIn |
Zdenek Nemecek, Jana Safrankova, Frantisek Nemec, Lubomir Prech, Alexander Pitna, Christopher H. K. Chen, Georgy N. Zastenker |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250104499
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| Publikation (Nr.) |
 EGU/EGU2015-3920.pdf |
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| Zusammenfassung |
| The paper presents a large statistical analysis of ≈ 5800 frequency spectra of the solar
wind density fluctuations in the range of 0.001–5ÂHz (corresponding spatial scales
100–5x105 km). The analysis confirms that the spectrum consists of three segments divided
by two breakpoints and that both breakpoint locations are controlled by the gyrostructure
frequency, fg defined as a ratio of the solar wind bulk speed and thermal ion gyroradius. Each
from three segments can be described by a power-law function with a spectral index where
the first segment corresponding to the MHD scale is followed by a plateau, and the third
segment can be associated with kinetic turbulence. As it follows from the statistics, the values
of spectral indices depend on the density fluctuation level; its increasing level leads to
steepening of each segment. The index -1.8 can be typically found at MHD scales and
averaging of spectra in the frequency domain leads to the index of -8/3 at kinetic
scales, whereas averaging in frequencies normalized to fg provides a value of -7/3. |
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