Flux Braiding
The idea is that the convective motions in and below the photosphere moves the
foot points of the coronal magnetic field around. These perturbations then
propagate into the corona, where the dynamics is dominated by the magnetic
force. The coronal magnetic field will therefore constantly evolve towards a
state with minimum forces. As the field is stressed by the convective motions
this may not be possible and a state where magnetic singularities in the
from of current sheets will develop. In a non-ideal plasma, as the corona, this
will provide the locations for energy release through Joule dissipation and a
restructuring of the magnetic field line connectivity will take place. E.J.
Parker initially suggested that this mechanism can be responsible for heating
the solar corona. In collaboration with
Åke Nordlund, we have been making numerical 3D MHD experiments to
investigate the phenomena. The base line is that in a constantly driven field a
statistically equilibrium between the energy input and the dissipation will be
obtained however low the magnetic resistivity is. Our experiments have shown
that this equilibrium is reach through the formation of an ensemble of non-
stationary current sheet fragments.
Papers
- Coronal Heating by Flux Braiding (7.4 Mb), "Solar and Astronomical Magnetohydrodynamic Flows" Crete, Greece, June 1995 (Astro. Lett. and Communications, Vol. 34, p 175, 1996).
- The Heating and Activity of the Solar Corona: 1. Boundary Shearing of an Initially Homogeneous Magnetic Field (9 Mb) (JGR, 101, 13445-13460, 1996)
Last updated 12.06.00