Work

Current sheet formation and nonideal behavior at three-dimensional magnetic null points

Year: 2007

Type: article

Abstract: The nature of the evolution of the magnetic field, and of current sheet formation, at three-dimensional (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 time-dependent), 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.

Source: Physics of Plasmas

DOI: 10.1063/1.2722300

Authors: D. I. Pontin, A. Bhattacharjee, K. Galsgaard

Institutions: University of New Hampshire, University of Dundee, University of Copenhagen

Language: English

Topic: Solar and Space Plasma Dynamics

Subfield: Astronomy and Astrophysics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: green

Funders: National Science Foundation, U.S. Department of Energy, National Aeronautics and Space Administration

Awards: Role of Collisionless Reconnection Mechanisms in Solar Flares and Coronal Mass Ejections (CMEs), G222768804, HEATING THE CORONA AND THE SOLAR WIND BY MAGNETIC RECONNECTION, RECONNECTION RESEARCH AT CMSO, Collaborative Research: Global Simulations of Substorm Trigger with GGCM: Synergistic Coupling of Magnetic Reconnection and Ballooning-Interchange Instabilities in the Magnetotail