Journal Article

Electric and magnetic spectra from MHD to electron scales in the magnetosheath

L. Matteini, O. Alexandrova, C. H. K. Chen and C. Lacombe

in Monthly Notices of the Royal Astronomical Society

Published on behalf of Royal Astronomical Society

Volume 466, issue 1, pages 945-951
ISSN: 0035-8711
Published online December 2016 | e-ISSN: 1365-2966 | DOI: http://dx.doi.org/10.1093/mnras/stw3163
Electric and magnetic spectra from MHD to electron scales in the magnetosheath

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Abstract

We investigate the transition of the turbulence from large to kinetic scales using Cluster observations. Simultaneous spectra of magnetic and electric fields in the Earth's magnetosheath from magnetohydrodynamic (MHD) to electron scales are presented for the first time. While the two spectra have approximatively similar behaviour in the fluid-MHD regime, they show different trends in the kinetic range. As the magnetic field spectrum steepens at ion scales, the electric field spectrum is characterized by a shallower power law continuing down to electron scales. Such an evolution is consistent with theoretical expectations, assuming that the turbulence is dominated by highly oblique [math]-vectors and that between ion and electron scales the electric field is governed by the non-ideal terms in the generalized Ohm's law. This leads to an expected linear increase of the electric-to-magnetic ratio of fluctuations, consistent with observations presented here. The influence of local whistler wave activity on electron-scale spectra is also discussed.

Keywords: magnetic fields; MHD; plasmas; turbulence; solar wind

Journal Article.  6118 words.  Illustrated.

Subjects: Astronomy and Astrophysics

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