Wyper, P. and Jain, R. (2013) 'Reconnection at three dimensional magnetic null points: Effect of current sheet asymmetry.', Physics of plasmas., 20 (5). 052901.
Asymmetric current sheets are likely to be prevalent in both astrophysical and laboratory plasmas with complex three dimensional (3D) magnetic topologies. This work presents kinematic analytical models for spine and fan reconnection at a radially symmetric 3D null (i.e., a null where the eigenvalues associated with the fan plane are equal) with asymmetric current sheets. Asymmetric fan reconnection is characterized by an asymmetric reconnection of flux past each spine line and a bulk flow of plasma across the null point. In contrast, asymmetric spine reconnection is characterized by the reconnection of an equal quantity of flux across the fan plane in both directions. The higher modes of spine reconnection also include localized wedges of vortical flux transport in each half of the fan. In this situation, two definitions for reconnection rate become appropriate: a local reconnection rate quantifying how much flux is genuinely reconnected across the fan plane and a global rate associated with the net flux driven across each semi-plane. Through a scaling analysis, it is shown that when the ohmic dissipation in the layer is assumed to be constant, the increase in the local rate bleeds from the global rate as the sheet deformation is increased. Both models suggest that asymmetry in the current sheet dimensions will have a profound effect on the reconnection rate and manner of flux transport in reconnection involving 3D nulls.
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|Publisher Web site:||https://doi.org/10.1063/1.4804338|
|Publisher statement:||© 2013 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Wyper, P. & Jain, R. (2013). Reconnection at three dimensional magnetic null points: Effect of current sheet asymmetry. Physics of Plasmas 20(5): 052901 and may be found at https://doi.org/10.1063/1.4804338|
|Date accepted:||23 April 2013|
|Date deposited:||29 March 2017|
|Date of first online publication:||10 May 2013|
|Date first made open access:||No date available|
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