Energy spectrum of tearing mode turbulence in sheared background field

doi:10.1063/1.5022292

Title: Energy spectrum of tearing mode turbulence in sheared background field

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Abstract

The energy spectrum of tearing mode turbulence in a sheared background magnetic field is explored in this work. We observe the scenario where the nonlinear interaction of overlapping large-scale modes excites a broad spectrum of small-scale modes, generating tearing mode turbulence. The spectrum of such turbulence is of interest since it is relevant to the small-scale back-reaction on the large-scale field. The turbulence we report on here differs from traditional MHD turbulence mainly in two aspects. One is the existence of many linearly stable small-scale modes which cause an effective damping during the energy cascade. The other is the scale-independent anisotropy induced by the large-scale modes tilting the sheared background field, as opposed to the scale-dependent anisotropy frequently encountered in traditional critically balanced turbulence theories. Due to these two differences, the energy spectrum deviates from a simple power law and takes the form of a power law multiplied by an exponential falloff. Numerical simulations are carried out using visco-resistive MHD equations to verify our theoretical predictions, and a reasonable agreement is found between the numerical results and our model.

Authors:

Hu, Di ^[1]; Bhattacharjee, Amitava ^[2];

^[2]

Peking Univ., Beijing (China); ITER Organization, St. Paul Lez Durance (France); Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Princeton Univ., NJ (United States); Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)

Publication Date:: 2018-06-06

Research Org.:: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC); Princeton Univ., NJ (United States)

Sponsoring Org.:: USDOE Office of Science (SC); National Natural Science Foundation of China (NNSFC); China Scholarship Council

OSTI Identifier:: 1543854

Grant/Contract Number:: SC0016470

Resource Type:: Accepted Manuscript

Journal Name:: Physics of Plasmas

Additional Journal Information:: Journal Volume: 25; Journal Issue: 6; Journal ID: ISSN 1070-664X

Publisher:: American Institute of Physics (AIP)

Country of Publication:: United States

Language:: English

Subject:: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY

Citation Formats


                    Hu, Di, Bhattacharjee, Amitava, and Huang, Yi-Min. Energy spectrum of tearing mode turbulence in sheared background field.  United States: N. p., 2018. 
        Web.  doi:10.1063/1.5022292.

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                    Hu, Di, Bhattacharjee, Amitava, & Huang, Yi-Min. Energy spectrum of tearing mode turbulence in sheared background field.  United States.  doi:10.1063/1.5022292.

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                    Hu, Di, Bhattacharjee, Amitava, and Huang, Yi-Min. Wed .  
        "Energy spectrum of tearing mode turbulence in sheared background field".  United States.  doi:10.1063/1.5022292.  https://www.osti.gov/servlets/purl/1543854.

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@article{osti_1543854,

  title        = {Energy spectrum of tearing mode turbulence in sheared background field},

  author       = {Hu, Di and Bhattacharjee, Amitava and Huang, Yi-Min},

  abstractNote = {The energy spectrum of tearing mode turbulence in a sheared background magnetic field is explored in this work. We observe the scenario where the nonlinear interaction of overlapping large-scale modes excites a broad spectrum of small-scale modes, generating tearing mode turbulence. The spectrum of such turbulence is of interest since it is relevant to the small-scale back-reaction on the large-scale field. The turbulence we report on here differs from traditional MHD turbulence mainly in two aspects. One is the existence of many linearly stable small-scale modes which cause an effective damping during the energy cascade. The other is the scale-independent anisotropy induced by the large-scale modes tilting the sheared background field, as opposed to the scale-dependent anisotropy frequently encountered in traditional critically balanced turbulence theories. Due to these two differences, the energy spectrum deviates from a simple power law and takes the form of a power law multiplied by an exponential falloff. Numerical simulations are carried out using visco-resistive MHD equations to verify our theoretical predictions, and a reasonable agreement is found between the numerical results and our model.},

  doi          = {10.1063/1.5022292},

  journal      = {Physics of Plasmas},

  number       = 6,

  volume       = 25,

  place        = {United States},

  year         = {2018},

  month        = {6}

}

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