Spontaneous Formation of Electric Current Sheets by the Expulsion of Magnetic Flux
Abstract
Two theoretical examples are given to demonstrate the spontaneous formation of electric current sheets in force-free magnetic fields frozen into a medium with an infinite electrical conductivity, as a result of the continuous displacement of the magnetic footpoints at the boundary. An initial three-lobe axisymmetric magnetic field without neutral points in the infinite medium outside a unit sphere is found to adjust to footpoint displacements by a slipping of the central lobe relative to the other two lobes. Also, a three-dimensional force-free magnetic field is studied, showing that conditions for the expulsion of flux from a local region to bring spatially separate fluxes together to form rotational discontinuities are readily obtained between ordinary magnetic surfaces.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- May 1989
- DOI:
- 10.1086/167417
- Bibcode:
- 1989ApJ...340..558L
- Keywords:
-
- Current Sheets;
- Electric Current;
- Solar Magnetic Field;
- Force-Free Magnetic Fields;
- Magnetic Flux;
- Plasma Physics;
- HYDROMAGNETICS;
- SUN: MAGNETIC FIELDS