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Title: Non-linear tearing of 3D null point current sheets

Abstract

The manner in which the rate of magnetic reconnection scales with the Lundquist number in realistic three-dimensional (3D) geometries is still an unsolved problem. It has been demonstrated that in 2D rapid non-linear tearing allows the reconnection rate to become almost independent of the Lundquist number (the “plasmoid instability”). Here, we present the first study of an analogous instability in a fully 3D geometry, defined by a magnetic null point. The 3D null current layer is found to be susceptible to an analogous instability but is marginally more stable than an equivalent 2D Sweet-Parker-like layer. Tearing of the sheet creates a thin boundary layer around the separatrix surface, contained within a flux envelope with a hyperbolic structure that mimics a spine-fan topology. Efficient mixing of flux between the two topological domains occurs as the flux rope structures created during the tearing process evolve within this envelope. This leads to a substantial increase in the rate of reconnection between the two domains.

Authors:
;  [1]
  1. Division of Mathematics, University of Dundee, Dundee (United Kingdom)
Publication Date:
OSTI Identifier:
22303764
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 21; Journal Issue: 8; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; BOUNDARY LAYERS; CURRENTS; INSTABILITY; MAGNETIC RECONNECTION; NONLINEAR PROBLEMS

Citation Formats

Wyper, P. F., E-mail: peterw@maths.dundee.ac.uk, and Pontin, D. I., E-mail: dpontin@maths.dundee.ac.uk. Non-linear tearing of 3D null point current sheets. United States: N. p., 2014. Web. doi:10.1063/1.4893149.
Wyper, P. F., E-mail: peterw@maths.dundee.ac.uk, & Pontin, D. I., E-mail: dpontin@maths.dundee.ac.uk. Non-linear tearing of 3D null point current sheets. United States. doi:10.1063/1.4893149.
Wyper, P. F., E-mail: peterw@maths.dundee.ac.uk, and Pontin, D. I., E-mail: dpontin@maths.dundee.ac.uk. Fri . "Non-linear tearing of 3D null point current sheets". United States. doi:10.1063/1.4893149.
@article{osti_22303764,
title = {Non-linear tearing of 3D null point current sheets},
author = {Wyper, P. F., E-mail: peterw@maths.dundee.ac.uk and Pontin, D. I., E-mail: dpontin@maths.dundee.ac.uk},
abstractNote = {The manner in which the rate of magnetic reconnection scales with the Lundquist number in realistic three-dimensional (3D) geometries is still an unsolved problem. It has been demonstrated that in 2D rapid non-linear tearing allows the reconnection rate to become almost independent of the Lundquist number (the “plasmoid instability”). Here, we present the first study of an analogous instability in a fully 3D geometry, defined by a magnetic null point. The 3D null current layer is found to be susceptible to an analogous instability but is marginally more stable than an equivalent 2D Sweet-Parker-like layer. Tearing of the sheet creates a thin boundary layer around the separatrix surface, contained within a flux envelope with a hyperbolic structure that mimics a spine-fan topology. Efficient mixing of flux between the two topological domains occurs as the flux rope structures created during the tearing process evolve within this envelope. This leads to a substantial increase in the rate of reconnection between the two domains.},
doi = {10.1063/1.4893149},
journal = {Physics of Plasmas},
number = 8,
volume = 21,
place = {United States},
year = {Fri Aug 15 00:00:00 EDT 2014},
month = {Fri Aug 15 00:00:00 EDT 2014}
}