Anisotropy of solar wind turbulence in the inner heliosphere at kinetic scales: PSP observations
File(s)2102.13294v2.pdf (1.14 MB)
Accepted version
Author(s)
Type
Journal Article
Abstract
The anisotropy of solar wind turbulence is a critical issue in understanding the physics of energy transfer between scales and energy conversion between fields and particles in the heliosphere. Using the measurement of Parker Solar Probe (PSP), we present an observation of the anisotropy at kinetic scales in the slow, Alfvénic, solar wind in the inner heliosphere. The magnetic compressibility behaves as expected for kinetic Alfvénic turbulence below the ion scale. A steepened transition range is found between the inertial and kinetic ranges in all directions with respect to the local background magnetic field direction. The anisotropy of k⊥ ≫ k∥ is found evident in both transition and kinetic ranges, with the power anisotropy P⊥/P∥ > 10 in the kinetic range leading over that in the transition range and being stronger than that at 1 au. The spectral index varies from αt∥ = −5.7 ± 1.0 to αt⊥ = −3.7 ± 0.3 in the transition range and αk∥ = −3.12 ± 0.22 to αk⊥ = −2.57 ± 0.09 in the kinetic range. The corresponding wavevector anisotropy has the scaling of ${k}_{\parallel }\sim {k}_{\perp }^{0.71\pm 0.17}$ in the transition range, and changes to ${k}_{\parallel }\sim {k}_{\perp }^{0.38\pm 0.09}$ in the kinetic range, consistent with the kinetic Alfvénic turbulence at sub-ion scales.
Date Issued
2021-07
Date Acceptance
2021-05-31
Citation
Letters of the Astrophysical Journal, 2021, 915, pp.1-7
ISSN
2041-8205
Publisher
American Astronomical Society
Start Page
1
End Page
7
Journal / Book Title
Letters of the Astrophysical Journal
Volume
915
Copyright Statement
© 2021. The American Astronomical Society. All rights reserved.
Identifier
https://iopscience.iop.org/article/10.3847/2041-8213/ac07ac
Subjects
Science & Technology
Physical Sciences
Astronomy & Astrophysics
PLASMA TURBULENCE
physics.space-ph
physics.space-ph
astro-ph.SR
Astronomy & Astrophysics
0201 Astronomical and Space Sciences
Notes
keywords: Solar wind, Interplanetary turbulence, Alfven waves, 1534, 830, 23, Physics - Space Physics, Astrophysics - Solar and Stellar Astrophysics eid: L8 archiveprefix: arXiv primaryclass: physics.space-ph adsurl: https://ui.adsabs.harvard.edu/abs/2021ApJ...915L...8D adsnote: Provided by the SAO/NASA Astrophysics Data System
Publication Status
Published
Article Number
1
Date Publish Online
2021-06-30