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Title: The impact of small-scale turbulence on laminar magnetic reconnection

Abstract

Initial states in incompressible two-dimensional magnetohydrodynamics that are known to lead to strong current sheets and (laminar) magnetic reconnection are modified by the addition of small-scale turbulent perturbations of various energies. The evolution of these states is computed with the aim of ascertaining the influence of the turbulence on the underlying laminar solution. Two main questions are addressed here: (1) What effect does small-scale turbulence have on the energy dissipation rate of the underlying solution? (2) What is the threshold turbulent perturbation level above which the original laminar reconnective dynamics is no longer recognizable. The simulations show that while the laminar dynamics persist the dissipation rates are largely unaffected by the turbulence, other than modest increases attributable to the additional small length scales present in the new initial condition. The solutions themselves are also remarkably insensitive to small-scale turbulent perturbations unless the perturbations are large enough to undermine the integrity of the underlying cellular flow pattern. Indeed, even initial states that lead to the evolution of small-scale microscopic sheets can survive the addition of modest turbulence. The role of a large-scale organizing background magnetic field is also addressed.

Authors:
; ;  [1];  [2]
  1. School of Physics, University of Sydney, NSW 2006 (Australia)
  2. (New Zealand)
Publication Date:
OSTI Identifier:
20974873
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 14; Journal Issue: 3; Other Information: DOI: 10.1063/1.2458595; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; DISTURBANCES; ENERGY LOSSES; LAMINAR FLOW; MAGNETIC FIELDS; MAGNETIC RECONNECTION; MAGNETOHYDRODYNAMICS; PLASMA; PLASMA SIMULATION; TURBULENCE

Citation Formats

Watson, P. G., Oughton, S., Craig, I. J. D., and Department of Mathematics, University of Waikato, Private Bag 3105, Hamilton. The impact of small-scale turbulence on laminar magnetic reconnection. United States: N. p., 2007. Web. doi:10.1063/1.2458595.
Watson, P. G., Oughton, S., Craig, I. J. D., & Department of Mathematics, University of Waikato, Private Bag 3105, Hamilton. The impact of small-scale turbulence on laminar magnetic reconnection. United States. doi:10.1063/1.2458595.
Watson, P. G., Oughton, S., Craig, I. J. D., and Department of Mathematics, University of Waikato, Private Bag 3105, Hamilton. Thu . "The impact of small-scale turbulence on laminar magnetic reconnection". United States. doi:10.1063/1.2458595.
@article{osti_20974873,
title = {The impact of small-scale turbulence on laminar magnetic reconnection},
author = {Watson, P. G. and Oughton, S. and Craig, I. J. D. and Department of Mathematics, University of Waikato, Private Bag 3105, Hamilton},
abstractNote = {Initial states in incompressible two-dimensional magnetohydrodynamics that are known to lead to strong current sheets and (laminar) magnetic reconnection are modified by the addition of small-scale turbulent perturbations of various energies. The evolution of these states is computed with the aim of ascertaining the influence of the turbulence on the underlying laminar solution. Two main questions are addressed here: (1) What effect does small-scale turbulence have on the energy dissipation rate of the underlying solution? (2) What is the threshold turbulent perturbation level above which the original laminar reconnective dynamics is no longer recognizable. The simulations show that while the laminar dynamics persist the dissipation rates are largely unaffected by the turbulence, other than modest increases attributable to the additional small length scales present in the new initial condition. The solutions themselves are also remarkably insensitive to small-scale turbulent perturbations unless the perturbations are large enough to undermine the integrity of the underlying cellular flow pattern. Indeed, even initial states that lead to the evolution of small-scale microscopic sheets can survive the addition of modest turbulence. The role of a large-scale organizing background magnetic field is also addressed.},
doi = {10.1063/1.2458595},
journal = {Physics of Plasmas},
number = 3,
volume = 14,
place = {United States},
year = {Thu Mar 15 00:00:00 EDT 2007},
month = {Thu Mar 15 00:00:00 EDT 2007}
}