The shape of twisted, line-tied coronal loops
Abstract
The magnetostatic equilibrium of a coronal loop in response to slow twisting of the photospheric footpoints is investigated. A numerical code is used to solve the full non-linear 2-D axisymmetric problem, extending earlier linearised models which assume weak twist and large aspect ratio. It is found that often the core of the loop tends to contract into a region of strong longitudinal field while the outer part expands. It is shown that, away from the photospheric footpoints, the equilibrium is very well approximated by a straight 1-D cylindrical model. This idea is used to develop a simple method for prescribing the footpoint angular displacement and calculating the equilibrium.
- Publication:
-
Solar Physics
- Pub Date:
- September 1989
- DOI:
- 10.1007/BF00156270
- Bibcode:
- 1989SoPh..124..271B
- Keywords:
-
- Coronal Loops;
- Photosphere;
- Solar Magnetic Field;
- Current Density;
- Iterative Solution;
- Magnetic Field Configurations;
- Magnetohydrodynamics;
- Solar Physics;
- Aspect Ratio;
- Outer Part;
- Angular Displacement;
- Numerical Code;
- Coronal Loop