Current singularities at finitely compressible three-dimensional magnetic null points

Journal Article · Fri Jul 15 04:00:00 EDT 2005 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.1987379· OSTI ID:20764376

Pontin, D I; Craig, I J.D. ^[1]

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1. Department of Mathematics, University of Waikato, Private Bag 3105, Hamilton (New Zealand)

The formation of current singularities at line-tied two- and three-dimensional (2D and 3D, respectively) magnetic null points in a nonresistive magnetohydrodynamic environment is explored. It is shown that, despite the different separatrix structures of 2D and 3D null points, current singularities may be initiated in a formally equivalent manner. This is true no matter whether the collapse is triggered by flux imbalance within closed, line-tied null points or driven by externally imposed velocity fields in open, incompressible geometries. A Lagrangian numerical code is used to investigate the finite amplitude perturbations that lead to singular current sheets in collapsing 2D and 3D null points. The form of the singular current distribution is analyzed as a function of the spatial anisotropy of the null point, and the effects of finite gas pressure are quantified. It is pointed out that the pressure force, while never stopping the formation of the singularity, significantly alters the morphology of the current distribution as well as dramatically weakening its strength. The impact of these findings on 2D and 3D magnetic reconnection models is discussed.

• OSTI ID: 20764376
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 7 Vol. 12; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ABSORPTION
AMPLITUDES
ANISOTROPY
CHARGED-PARTICLE TRANSPORT
DISTRIBUTION
DISTURBANCES
ELECTRIC CURRENTS
GEOMETRY
LAGRANGIAN FUNCTION
MAGNETIC RECONNECTION
MAGNETOHYDRODYNAMICS
MORPHOLOGY
PLASMA
PLASMA PRESSURE
SINGULARITY
THREE-DIMENSIONAL CALCULATIONS
VELOCITY