Current sheet formation and nonideal behavior at threedimensional magnetic null points
Abstract
The nature of the evolution of the magnetic field, and of current sheet formation, at threedimensional (3D) magnetic null points is investigated. A kinematic example is presented that demonstrates that for certain evolutions of a 3D null (specifically those for which the ratios of the null point eigenvalues are timedependent), there is no possible choice of boundary conditions that renders the evolution of the field at the null ideal. Resistive magnetohydrodynamics simulations are described that demonstrate that such evolutions are generic. A 3D null is subjected to boundary driving by shearing motions, and it is shown that a current sheet localized at the null is formed. The qualitative and quantitative properties of the current sheet are discussed. Accompanying the sheet development is the growth of a localized parallel electric field, one of the signatures of magnetic reconnection. Finally, the relevance of the results to a recent theory of turbulent reconnection is discussed.
 Authors:
 Space Science Center and Center for Magnetic SelfOrganization, University of New Hampshire, Durham, New Hampshire 03824 (United States)
 (Denmark)
 Publication Date:
 OSTI Identifier:
 20974966
 Resource Type:
 Journal Article
 Resource Relation:
 Journal Name: Physics of Plasmas; Journal Volume: 14; Journal Issue: 5; Other Information: DOI: 10.1063/1.2722300; (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; BOUNDARY CONDITIONS; EIGENVALUES; ELECTRIC FIELDS; MAGNETIC FIELDS; MAGNETIC RECONNECTION; MAGNETOHYDRODYNAMICS; PLASMA; PLASMA SHEATH; PLASMA SIMULATION; SHEAR; THREEDIMENSIONAL CALCULATIONS; TIME DEPENDENCE; TURBULENCE
Citation Formats
Pontin, D. I., Bhattacharjee, A., Galsgaard, K., and Niels Bohr Institute, University of Copenhagen, Copenhagen. Current sheet formation and nonideal behavior at threedimensional magnetic null points. United States: N. p., 2007.
Web. doi:10.1063/1.2722300.
Pontin, D. I., Bhattacharjee, A., Galsgaard, K., & Niels Bohr Institute, University of Copenhagen, Copenhagen. Current sheet formation and nonideal behavior at threedimensional magnetic null points. United States. doi:10.1063/1.2722300.
Pontin, D. I., Bhattacharjee, A., Galsgaard, K., and Niels Bohr Institute, University of Copenhagen, Copenhagen. Tue .
"Current sheet formation and nonideal behavior at threedimensional magnetic null points". United States.
doi:10.1063/1.2722300.
@article{osti_20974966,
title = {Current sheet formation and nonideal behavior at threedimensional magnetic null points},
author = {Pontin, D. I. and Bhattacharjee, A. and Galsgaard, K. and Niels Bohr Institute, University of Copenhagen, Copenhagen},
abstractNote = {The nature of the evolution of the magnetic field, and of current sheet formation, at threedimensional (3D) magnetic null points is investigated. A kinematic example is presented that demonstrates that for certain evolutions of a 3D null (specifically those for which the ratios of the null point eigenvalues are timedependent), there is no possible choice of boundary conditions that renders the evolution of the field at the null ideal. Resistive magnetohydrodynamics simulations are described that demonstrate that such evolutions are generic. A 3D null is subjected to boundary driving by shearing motions, and it is shown that a current sheet localized at the null is formed. The qualitative and quantitative properties of the current sheet are discussed. Accompanying the sheet development is the growth of a localized parallel electric field, one of the signatures of magnetic reconnection. Finally, the relevance of the results to a recent theory of turbulent reconnection is discussed.},
doi = {10.1063/1.2722300},
journal = {Physics of Plasmas},
number = 5,
volume = 14,
place = {United States},
year = {Tue May 15 00:00:00 EDT 2007},
month = {Tue May 15 00:00:00 EDT 2007}
}

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