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www.nonlin-processes-geophys.net/16/691/2009/
doi:10.5194/npg-16-691-2009
© Author(s) 2009. This work is distributed
under the Creative Commons Attribution 3.0 License.
Variability of magnetic field spectra in the Earth's magnetotail
Space Research Institute, 84/32 Profsoyuznaya st., Moscow, 117997, Russia
Moscow Institute of Physics and Technology, Moscow, Russia
Abstract. We investigate the variability of magnetic fluctuation spectra below 1 Hz in the Earth's plasma sheet using specially selected long observation intervals by Geotail spacecraft. The spectra can be generally described by a negative power law with two kinks. The range between kinks ~0.02–0.2 Hz has the most stable power law index ~2.4–2.6. Indices at the lower and the higher frequencies are more variable and generally increase with power of fluctuations. In the sub-second range fluctuations are strongly localized and indices are closer to 3. At the lower-frequency end indices are about 1.5. The lower kink is usually well defined on average spectra and its frequency tends to increase with activity. Combination of spectrum index α and fractal dimension δ is expected to follow the Berry relation α+2δ=5, but actually is ~5.5.
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Citation: Petrukovich, A. A. and Malakhov, D. V.: Variability of magnetic field spectra in the Earth's magnetotail, Nonlin. Processes Geophys., 16, 691-698, doi:10.5194/npg-16-691-2009, 2009. Bibtex EndNote Reference Manager XML
