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Title: Plasma turbulence driven by transversely large-scale standing shear Alfven waves

Abstract

Using two-dimensional particle-in-cell simulations, we study generation of turbulence consisting of transversely small-scale dispersive Alfven and electrostatic waves when plasma is driven by a large-scale standing shear Alfven wave (LS-SAW). The standing wave is set up by reflecting a propagating LS-SAW. The ponderomotive force of the standing wave generates transversely large-scale density modifications consisting of density cavities and enhancements. The drifts of the charged particles driven by the ponderomotive force and those directly caused by the fields of the standing LS-SAW generate non-thermal features in the plasma. Parametric instabilities driven by the inherent plasma nonlinearities associated with the LS-SAW in combination with the non-thermal features generate small-scale electromagnetic and electrostatic waves, yielding a broad frequency spectrum ranging from below the source frequency of the LS-SAW to ion cyclotron and lower hybrid frequencies and beyond. The power spectrum of the turbulence has peaks at distinct perpendicular wave numbers (k{sub Up-Tack }) lying in the range d{sub e}{sup -1}-6d{sub e}{sup -1}, d{sub e} being the electron inertial length, suggesting non-local parametric decay from small to large k{sub Up-Tack }. The turbulence spectrum encompassing both electromagnetic and electrostatic fluctuations is also broadband in parallel wave number (k{sub ||}). In a standing-wave supported densitymore » cavity, the ratio of the perpendicular electric to magnetic field amplitude is R(k{sub Up-Tack }) = |E{sub Up-Tack }(k{sub Up-Tack })/|B{sub Up-Tack }(k{sub Up-Tack })| Much-Less-Than V{sub A} for k{sub Up-Tack }d{sub e} < 0.5, where V{sub A} is the Alfven velocity. The characteristic features of the broadband plasma turbulence are compared with those available from satellite observations in space plasmas.« less

Authors:
;  [1]
  1. Electrical and Computer Engineering, University of Alabama, Huntsville, Alabama 35899 (United States)
Publication Date:
OSTI Identifier:
22072619
Resource Type:
Journal Article
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 19; Journal Issue: 12; Other Information: (c) 2012 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1070-664X
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ALFVEN WAVES; ELECTRONS; ION CYCLOTRON-RESONANCE; LOWER HYBRID HEATING; MAGNETIC FIELDS; NONLINEAR PROBLEMS; PARAMETRIC INSTABILITIES; PLASMA; PLASMA DENSITY; PLASMA SIMULATION; PLASMA WAVES; PONDEROMOTIVE FORCE; STANDING WAVES; TURBULENCE; TWO-DIMENSIONAL CALCULATIONS

Citation Formats

Singh, Nagendra, and Rao, Sathyanarayan. Plasma turbulence driven by transversely large-scale standing shear Alfven waves. United States: N. p., 2012. Web. doi:10.1063/1.4769851.
Singh, Nagendra, & Rao, Sathyanarayan. Plasma turbulence driven by transversely large-scale standing shear Alfven waves. United States. doi:10.1063/1.4769851.
Singh, Nagendra, and Rao, Sathyanarayan. Sat . "Plasma turbulence driven by transversely large-scale standing shear Alfven waves". United States. doi:10.1063/1.4769851.
@article{osti_22072619,
title = {Plasma turbulence driven by transversely large-scale standing shear Alfven waves},
author = {Singh, Nagendra and Rao, Sathyanarayan},
abstractNote = {Using two-dimensional particle-in-cell simulations, we study generation of turbulence consisting of transversely small-scale dispersive Alfven and electrostatic waves when plasma is driven by a large-scale standing shear Alfven wave (LS-SAW). The standing wave is set up by reflecting a propagating LS-SAW. The ponderomotive force of the standing wave generates transversely large-scale density modifications consisting of density cavities and enhancements. The drifts of the charged particles driven by the ponderomotive force and those directly caused by the fields of the standing LS-SAW generate non-thermal features in the plasma. Parametric instabilities driven by the inherent plasma nonlinearities associated with the LS-SAW in combination with the non-thermal features generate small-scale electromagnetic and electrostatic waves, yielding a broad frequency spectrum ranging from below the source frequency of the LS-SAW to ion cyclotron and lower hybrid frequencies and beyond. The power spectrum of the turbulence has peaks at distinct perpendicular wave numbers (k{sub Up-Tack }) lying in the range d{sub e}{sup -1}-6d{sub e}{sup -1}, d{sub e} being the electron inertial length, suggesting non-local parametric decay from small to large k{sub Up-Tack }. The turbulence spectrum encompassing both electromagnetic and electrostatic fluctuations is also broadband in parallel wave number (k{sub ||}). In a standing-wave supported density cavity, the ratio of the perpendicular electric to magnetic field amplitude is R(k{sub Up-Tack }) = |E{sub Up-Tack }(k{sub Up-Tack })/|B{sub Up-Tack }(k{sub Up-Tack })| Much-Less-Than V{sub A} for k{sub Up-Tack }d{sub e} < 0.5, where V{sub A} is the Alfven velocity. The characteristic features of the broadband plasma turbulence are compared with those available from satellite observations in space plasmas.},
doi = {10.1063/1.4769851},
journal = {Physics of Plasmas},
issn = {1070-664X},
number = 12,
volume = 19,
place = {United States},
year = {2012},
month = {12}
}