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| Titel |
Plasma beta control of scaling of solar wind turbulent structures |
| VerfasserIn |
Jana Safrankova, Zdenek Nemecek, Frantisek Nemec, Lubomir Prech, Christopher H. K. Chen, Georgy N. Zastenker |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250123405
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| Publikation (Nr.) |
 EGU/EGU2016-2648.pdf |
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| Zusammenfassung |
| The high-time resolution of Spektr-R plasma measurements allows us to make direct
observations of solar wind turbulence below ion kinetic length scales. The paper analyzes
solar wind power spectra of bulk and thermal speeds that are computed with a time resolution
of 32 ms in the frequency range of 0.001–2 Hz. The statistics based on more than 5000 of
individual spectra shows that: (1) the spectra of bulk and thermal speeds can be fitted by two
power-law segments; (2) despite their large variations, the parameters characterizing
frequency spectra fits computed on each particular time interval are very similar
for both quantities; (3) the median slopes of the segment attributed to the MHD
scale are −1.43 and −1.38, respectively for the bulk and thermal speeds, whereas
those in the kinetic scale are −3.08 and −2.43, respectively; (4) the break between
both MHD and kinetic scales is controlled the ion beta; and (5) the power index
corresponding to kinetic turbulence depends on a level of the density variations in the high
beta solar wind, whereas the ion gyromotion determines it for low beta intervals. |
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