Journal cover Journal topic
Annales Geophysicae Sun, Earth, planets, and planetary systems An interactive open-access journal of the European Geosciences Union
Ann. Geophys., 35, 1353-1360, 2017
https://doi.org/10.5194/angeo-35-1353-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 4.0 License.
ANGEO Communicates
15 Dec 2017
The usefulness of Poynting's theorem in magnetic turbulence
Rudolf A. Treumann1,a and Wolfgang Baumjohann2 1Department of Geophysics and Environmental Sciences, Munich University, Munich, Germany
2Space Research Institute, Austrian Academy of Sciences, Graz, Austria
avisiting scientist at: the International Space Science Institute, Bern, Switzerland
Abstract. We rewrite Poynting's theorem, already used in a previous publication Treumann and Baumjohann (2017a) to derive relations between the turbulent magnetic and electric power spectral densities, to make explicit where the mechanical contributions enter. We then make explicit use of the relativistic transformation of the turbulent electric fluctuations to obtain expressions which depend only on the magnetic and velocity fluctuations. Any electric fluctuations play just an intermediate role. Equations are constructed for the turbulent conductivity spectrum in Alfvénic and non-Alfvénic turbulence in extension of the results in the above citation. An observation-based discussion of their use in application to solar wind turbulence is given. The inertial range solar wind turbulence exhibits signs of chaos and self-organization.

Citation: Treumann, R. A. and Baumjohann, W.: The usefulness of Poynting's theorem in magnetic turbulence, Ann. Geophys., 35, 1353-1360, https://doi.org/10.5194/angeo-35-1353-2017, 2017.
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Short summary
Poynting's theorem provides a way to determine the spectrum of the dissipation function in magnetic turbulence. It is shown that it includes all contributions of the mechanical part of turbulence. Application to solar wind data identifies the inertial range as a state of self-organization and brings the Taylor hypothesis into question.
Poynting's theorem provides a way to determine the spectrum of the dissipation function in...
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