Dynamics of solar magnetic fields. VI. Forcefree magnetic fields and motions of magnetic footpoints.
Abstract
A mathematical model is developed to consider the evolution of forcefree magnetic fields in relation to the displacements of their footpoints. For a magnetic field depending on only two Cartesian coordinates and time, the problem reduces to solving a nonlinear elliptic partial differential equation. As illustration of the physical process, two specific examples of evolving forcefree magnetic fields are examined in detail, one evolving with rising and the other with descending field lines. It is shown that these two contrasting behaviors of the field lines correspond to sheared motions of their footpoints of quite different characters. The physical implications of these two examples of evolving forcefree magnetic fields are discussed.
 Publication:

The Astrophysical Journal
 Pub Date:
 July 1975
 DOI:
 10.1086/153686
 Bibcode:
 1975ApJ...199..237L
 Keywords:

 Astronomical Models;
 ForceFree Magnetic Fields;
 Magnetic Field Configurations;
 Magnetohydrodynamics;
 Photosphere;
 Solar Magnetic Field;
 Current Density;
 Elliptic Differential Equations;
 H Alpha Line;
 Mathematical Models;
 Solar Physics