Dynamical Evolution of a Solar Coronal Magnetic Field Arcade
Abstract
Calculations of the long-term dynamical evolution of a solar coronal magnetic field arcade which is subjected to shearing photospheric flows are presented. The evolution is obtained by numerical solution of a subset of the resistive magnetohydrodynamic equations. For a simplified model of the bipolar magnetic field observed in the solar corona, it is found that photospheric flow produces a slow evolution of the magnetic field, with a buildup of magnetic energy. For certain photospheric shear profiles, the field configuration produced is linearly unstable to an ideal magnetohydrodynamic mode when the shear exceeds a critical value. The nonlinear evolution of this instability shows the spontaneous formation of current sheets. Reconnection of the magnetic field produces a rapid release of magnetic energy. The major fraction of the energy is dissipated resistively, while a small fraction is converted into kinetic energy of an ejected plasmoid. The relevance of these results to two-ribbon flares is discussed.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- May 1988
- DOI:
- 10.1086/166341
- Bibcode:
- 1988ApJ...328..830M
- Keywords:
-
- Coronal Loops;
- Magnetohydrodynamic Flow;
- Solar Corona;
- Solar Flares;
- Solar Magnetic Field;
- Computational Astrophysics;
- Dynamic Characteristics;
- Kinetic Energy;
- Solar Physics;
- HYDROMAGNETICS;
- SUN: CORONA;
- SUN: MAGNETIC FIELDS