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

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:
 [1];  [2]; ORCiD logo [2]
  1. Peking Univ., Beijing (China); ITER Organization, St. Paul Lez Durance (France); Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
  2. Princeton Univ., NJ (United States); Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Publication Date:
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.
Hu, Di, Bhattacharjee, Amitava, & Huang, Yi-Min. Energy spectrum of tearing mode turbulence in sheared background field. United States. doi:10.1063/1.5022292.
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.
@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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