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| Titel |
Multifractal Turbulence in the Heliosphere |
| VerfasserIn |
Wieslaw M. Macek, Anna Wawrzaszek |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250032572
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| Zusammenfassung |
| We consider a solar wind plasma with frozen-in interplanetary magnetic fields, which is a
complex nonlinear system that may exhibit chaos and intermittency, resulting in a multifractal
scaling of plasma characteristics. We analyze time series of plasma velocity and
interplanetary magnetic field strengths measured during space missions onboard various
spacecraft, such as Helios, Advanced Composition Explorer, Ulysses, and Voyager, exploring
different regions of the heliosphere during solar minimum and maximum. To quantify the
multifractality of solar wind turbulence, we use a generalized two-scale weighted
Cantor set with two different rescaling parameters [1]. We investigate the resulting
spectrum of generalized dimensions and the corresponding multifractal singularity
spectrum depending on the parameters of this new cascade model [2]. We show
that using the model with two different scaling parameters one can explain the
multifractal singularity spectrum, which is often asymmetric. In particular, the multifractal
scaling of magnetic fields is asymmetric in the outer heliosphere, in contrast to the
symmetric spectrum observed in the heliosheath as described by the standard one-scale
model [3]. We hope that the generalized multifractal model will be a useful tool for
analysis of intermittent turbulence in the heliospheric plasma. We thus believe that
multifractal analysis of various complex environments can shed light on the nature of
turbulence.
[1] W. M. Macek and A. Szczepaniak, Generalized two-scale weighted Cantor
set model for solar wind turbulence, Geophys. Res. Lett., 35, L02108 (2008),
doi:10.1029/2007GL032263.
[2] W. M. Macek and A. Wawrzaszek, Evolution of asymmetric multifractal scaling of
solar wind turbulence in the outer heliosphere, J. Geophys. Res., A013795 (2009),
doi:10.1029/2008JA013795.
[3] W. M. Macek and A. Wawrzaszek, Multifractal turbulence at the termination shock, in
Solar Wind Twelve, edited by M. Maximovic et al., American Institute of Physics, 2010. |
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