Testing the effects of expansion on solar wind turbulence
File(s)
Published version
Author(s)
Vech, D
Chen, CHK
Type
Journal Article
Abstract
We present a multi-spacecraft approach to test the predictions of recent studies on the effect of solar wind expansion on the radial spectral, variance, and local 3D anisotropies of the turbulence. We found that on small scales (5000–10,000 km) the power levels of the B-trace structure functions do not depend on the sampling direction with respect to the radial suggesting that on this scale the effect of expansion is small possibly due to fast turbulent timescales. On larger scales (110–135 R E ), the fluctuations of the radial magnetic field component are reduced by ~20% compared to the transverse (perpendicular to radial) ones, which could be due to expansion confining the fluctuations into the plane perpendicular to radial. For the local 3D spectral anisotropy, the B-trace structure functions showed dependence on the sampling direction with respect to radial. The anisotropy in the perpendicular plane is reduced when the increments are taken perpendicular with respect to radial, which could be an effect of expansion.
Date Issued
2016-11-16
Date Acceptance
2016-10-27
Citation
Astrophysical Journal Letters, 2016, 832
ISSN
2041-8213
Publisher
American Astronomical Society
Journal / Book Title
Astrophysical Journal Letters
Volume
832
Copyright Statement
© 2016. The American Astronomical Society. All rights reserved.
Sponsor
Science and Technology Facilities Council (STFC)
Grant Number
ST/N003748/1
Publication Status
Published