Dynamic Phase Alignment in Inertial Alfven Turbulence

Milanese, Lucio M.; Loureiro, Nuno F.; Daschner, Maximilian; Boldyrev, Stanislav

doi:10.7910/DVN/AAS2ZA

Title: Dynamic Phase Alignment in Inertial Alfven Turbulence

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Abstract

In weakly-collisional plasma environments with sufficiently low electron beta, Alfvenic turbulence transforms into inertial Alfvenic turbulence at scales below the electron skin-depth. We argue that, in inertial Alfvenic turbulence, both energy and generalized kinetic helicity exhibit direct cascades. We demonstrate that the two cascades are compatible due to the existence of a strong scale-dependence of the phase alignment angle between velocity and magnetic field fluctuations, with the phase alignment angle scaling as proportional to the perpendicular wavenumber to the power of -1. The kinetic and magnetic energy spectra scale as the perpendicular wavenumber to the power of -5/3 and -11/3, respectively. As a result of the dual direct cascade, the generalized-helicity spectrum scales as the perpendicular wavenumber to the power of -5/3, implying progressive balancing of the turbulence as the cascade proceeds to smaller scales in the sub-electron-skin-depth range. Turbulent eddies exhibit a phase-space anisotropy, with the parallel wavenumber scaling as the perpendicular wavenumber to the power of 5/3, consistent with critically-balanced inertial Alfven fluctuations. Our results may be applicable to a variety of geophysical, space, and astrophysical environments, including the Earth's magnetosheath and ionosphere, solar corona, non-relativistic pair plasmas, as well as to strongly rotating non-ionized fluids.

Authors:

Milanese, Lucio M.; Loureiro, Nuno F.; Daschner, Maximilian; Boldyrev, Stanislav

OSTI

Publication Date:: 2021-06-24

DOE Contract Number:: FG02-91ER54109; SC0018266

Research Org.:: Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Plasma Science and Fusion Center; Univ. of Wisconsin, Madison, WI (United States)

Sponsoring Org.:: USDOE Office of Science (SC), Fusion Energy Sciences (FES)

Subject:: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY

OSTI Identifier:: 1887458

DOI:: https://doi.org/10.7910/DVN/AAS2ZA

Citation Formats


                    Milanese, Lucio M., Loureiro, Nuno F., Daschner, Maximilian, and Boldyrev, Stanislav. Dynamic Phase Alignment in Inertial Alfven Turbulence.  United States: N. p., 2021. 
        Web.  doi:10.7910/DVN/AAS2ZA.

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                    Milanese, Lucio M., Loureiro, Nuno F., Daschner, Maximilian, & Boldyrev, Stanislav. Dynamic Phase Alignment in Inertial Alfven Turbulence.  United States.  doi:https://doi.org/10.7910/DVN/AAS2ZA

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                    Milanese, Lucio M., Loureiro, Nuno F., Daschner, Maximilian, and Boldyrev, Stanislav. 2021.  
"Dynamic Phase Alignment in Inertial Alfven Turbulence".  United States.  doi:https://doi.org/10.7910/DVN/AAS2ZA.  https://www.osti.gov/servlets/purl/1887458. Pub date:Thu Jun 24 04:00:00 UTC 2021

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@article{osti_1887458,

  title        = {Dynamic Phase Alignment in Inertial Alfven Turbulence},

  author       = {Milanese, Lucio M. and Loureiro, Nuno F. and Daschner, Maximilian and Boldyrev, Stanislav},

  abstractNote = {In weakly-collisional plasma environments with sufficiently low electron beta, Alfvenic turbulence transforms into inertial Alfvenic turbulence at scales below the electron skin-depth. We argue that, in inertial Alfvenic turbulence, both energy and generalized kinetic helicity exhibit direct cascades. We demonstrate that the two cascades are compatible due to the existence of a strong scale-dependence of the phase alignment angle between velocity and magnetic field fluctuations, with the phase alignment angle scaling as proportional to the perpendicular wavenumber to the power of -1. The kinetic and magnetic energy spectra scale as the perpendicular wavenumber to the power of -5/3 and -11/3, respectively. As a result of the dual direct cascade, the generalized-helicity spectrum scales as the perpendicular wavenumber to the power of -5/3, implying progressive balancing of the turbulence as the cascade proceeds to smaller scales in the sub-electron-skin-depth range. Turbulent eddies exhibit a phase-space anisotropy, with the parallel wavenumber scaling as the perpendicular wavenumber to the power of 5/3, consistent with critically-balanced inertial Alfven fluctuations. Our results may be applicable to a variety of geophysical, space, and astrophysical environments, including the Earth's magnetosheath and ionosphere, solar corona, non-relativistic pair plasmas, as well as to strongly rotating non-ionized fluids.},

  doi          = {10.7910/DVN/AAS2ZA},

  journal      = {},

  number       = ,

  volume       = ,

  place        = {United States},

  year         = {2021},

  month        = {6}

}

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DOI: https://doi.org/10.7910/DVN/AAS2ZA

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