On the Evolution of the Anisotropic Scaling of Magnetohydrodynamic Turbulence in the Inner Heliosphere

Nikos Sioulas; Marco Velli; Zesen Huang; Chen Shi; Trevor A. Bowen; B. D. G. Chandran; Ioannis Liodis; Nooshin Davis; Stuart D. Bale; T. S. Horbury; Thierry Dudok de Wit; Davin Larson; Michael L. Stevens; Justin Kasper; Christopher J. Owen; Anthony Case; Marc Pulupa; David M. Malaspina; Roberto Livi; Keith Goetz; Peter R. Harvey; Robert J. MacDowall; John W. Bonnell

doi:10.3847/1538-4357/acc658

The Astrophysical Journal (Jan 2023)

On the Evolution of the Anisotropic Scaling of Magnetohydrodynamic Turbulence in the Inner Heliosphere

Nikos Sioulas,
Marco Velli,
Zesen Huang,
Chen Shi,
Trevor A. Bowen,
B. D. G. Chandran,
Ioannis Liodis,
Nooshin Davis,
Stuart D. Bale,
T. S. Horbury,
Thierry Dudok de Wit,
Davin Larson,
Michael L. Stevens,
Justin Kasper,
Christopher J. Owen,
Anthony Case,
Marc Pulupa,
David M. Malaspina,
Roberto Livi,
Keith Goetz,
Peter R. Harvey,
Robert J. MacDowall,
John W. Bonnell

Affiliations

Nikos Sioulas: ORCiD; Department of Earth, Planetary, and Space Sciences, University of California , Los Angeles, Los Angeles, CA 90095, USA ; [email protected]
Marco Velli: ORCiD; Department of Earth, Planetary, and Space Sciences, University of California , Los Angeles, Los Angeles, CA 90095, USA ; [email protected]; International Space Science Institute , 3012 Bern, Switzerland
Zesen Huang: ORCiD; Department of Earth, Planetary, and Space Sciences, University of California , Los Angeles, Los Angeles, CA 90095, USA ; [email protected]
Chen Shi: ORCiD; Department of Earth, Planetary, and Space Sciences, University of California , Los Angeles, Los Angeles, CA 90095, USA ; [email protected]
Trevor A. Bowen: ORCiD; Space Sciences Laboratory, University of California , Berkeley, CA 94720-7450, USA
B. D. G. Chandran: ORCiD; Space Science Center, University of New Hampshire , Durham, NH 03824, USA
Ioannis Liodis: ORCiD; Department of Physics, Aristotle University of Thessaloniki, GR-52124 Thessaloniki, Greece
Nooshin Davis: ORCiD; Space Science Center and Department of Physics, University of New Hampshire , Durham, NH 03824, USA
Stuart D. Bale: ORCiD; Space Sciences Laboratory, University of California , Berkeley, CA 94720-7450, USA; Physics Department, University of California , Berkeley, CA 94720-7300, USA
T. S. Horbury: ORCiD; The Blackett Laboratory, Imperial College London , London, UK
Thierry Dudok de Wit: ORCiD; LPC2E, CNRS and University of Orléans , Orléans, France
Davin Larson: ORCiD; Space Sciences Laboratory, University of California , Berkeley, CA 94720-7450, USA
Michael L. Stevens: ORCiD; Harvard-Smithsonian Center for Astrophysics , Cambridge, MA 02138, USA
Justin Kasper: ORCiD; BWX Technologies, Inc., Washington, DC 20002, USA; Climate and Space Sciences and Engineering, University of Michigan , Ann Arbor, MI 48109, USA
Christopher J. Owen: ORCiD; Mullard Space Science Laboratory, University College London , Dorking, RH5 6NT, UK
Anthony Case: ORCiD; Smithsonian Astrophysical Observatory , Cambridge, MA 02138, US
Marc Pulupa: ORCiD; Space Sciences Laboratory, University of California , Berkeley, CA 94720-7450, USA
David M. Malaspina: ORCiD; Astrophysical and Planetary Sciences Department, University of Colorado , Boulder, CO 80305, USA; Laboratory for Atmospheric and Space Physics, University of Colorado , Boulder, CO 80303, USA
Roberto Livi: ORCiD; Space Sciences Laboratory, University of California , Berkeley, CA 94720-7450, USA
Keith Goetz: ORCiD; School of Physics and Astronomy, University of Minnesota , Minneapolis, MN 55455, USA
Peter R. Harvey: ORCiD; Space Sciences Laboratory, University of California , Berkeley, CA 94720-7450, USA
Robert J. MacDowall: ORCiD; Solar System Exploration Division, NASA/Goddard Space Flight Center , Greenbelt, MD 20771, USA
John W. Bonnell: Space Sciences Laboratory, University of California , Berkeley, CA 94720-7450, USA

DOI: https://doi.org/10.3847/1538-4357/acc658
Journal volume & issue: Vol. 951, no. 2
p. 141

Abstract

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We analyze a merged Parker Solar Probe (PSP) and Solar Orbiter (SO) data set covering heliocentric distances 13 R _⊙ ≲ R ≲ 220 R _⊙ to investigate the radial evolution of power and spectral index anisotropy in the wavevector space of solar wind turbulence. Our results show that anisotropic signatures of turbulence display a distinct radial evolution when fast, V _sw ≥ 400 km s ^−1 , and slow, V _sw ≤ 400 km s ^−1 , wind streams are considered. The anisotropic properties of slow wind in Earth orbit are consistent with a “critically balanced” cascade, but both spectral index anisotropy and power anisotropy diminish with decreasing heliographic distance. Fast streams are observed to roughly retain their near-Sun anisotropic properties, with the observed spectral index and power anisotropies being more consistent with a “dynamically aligned” type of cascade, though the lack of extended fast wind intervals makes it difficult to accurately measure the anisotropic scaling. A high-resolution analysis during the first perihelion of PSP confirms the presence of two subranges within the inertial range, which may be associated with the transition from weak to strong turbulence. The transition occurs at κ d _i ≈ 6 × 10 ^−2 and signifies a shift from −5/3 to −2 and from −3/2 to −1.57 scaling in parallel and perpendicular spectra, respectively. Our results provide strong observational constraints for anisotropic theories of MHD turbulence in the solar wind.

Published in The Astrophysical Journal

ISSN: 1538-4357 (Online)
Publisher: IOP Publishing
Country of publisher: United Kingdom
LCC subjects: Science: Astronomy: Astrophysics
Website: https://iopscience.iop.org/journal/0004-637X

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