Non-linear tearing of 3D null point current sheets

Wyper, P.; Pontin, D.

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.

Citation

Wyper, P., & Pontin, D. (2014). Non-linear tearing of 3D null point current sheets. Physics of Plasmas, 21(8), Article 082114. https://doi.org/10.1063/1.4893149

• Journal Article Type: Article
• Acceptance Date: Aug 4, 2014
• Online Publication Date: Aug 15, 2014
• Publication Date: Aug 15, 2014
• Deposit Date: Oct 18, 2016
• Publicly Available Date: Mar 29, 2017
• Journal: Physics of Plasmas
• Print ISSN: 1070-664X
• Electronic ISSN: 1089-7674
• Publisher: American Institute of Physics
• Peer Reviewed: Peer Reviewed
• Volume: 21
• Issue: 8
• Article Number: 082114
• DOI: https://doi.org/10.1063/1.4893149
• Public URL: https://durham-repository.worktribe.com/output/1395169