Calculation of force-free magnetic field with non-constant α
Abstract
A numerical method is developed for solving the force-free magnetic field equation, ▽ × B = αB, with spatially-varying α. The boundary conditions required are the distribution of Bn (viz. normal component of the field on the photosphere) as well as the value of α in the region of positive (or negative) Bn. Examples of calculations are presented for a simple model of a solar bipolar magnetic region. It is found that the field configuration and the energy stored in the field depend crucially on the distribution of α. The present method can be applied to a more complex configuration observed on the Sun by making use of actual magnetic field measurements.
- Publication:
-
Solar Physics
- Pub Date:
- February 1981
- DOI:
- 10.1007/BF00149999
- Bibcode:
- 1981SoPh...69..343S
- Keywords:
-
- Boundary Condition;
- Magnetic Field;
- Simple Model;
- Field Equation;
- Present Method