ASYMPTOTIC ANALYSIS OF FORCE-FREE MAGNETIC-FIELDS OF CYLINDRICAL SYMMETRY

It is known from computer calculations that if a force-free magnetic-h eld configuration is stressed progressively by footpoint displacements , the configuration expands and approaches the open configuration with the same surface flux distribution, and, in the process, the energy o f the held increases progressively. Analysis of a simple model of forc e-free fields of cylindrical symmetry leads to simple asymptotic expre ssions for the extent and energy of such a configuration. The analysis is carried through for both spherical and planar source surfaces. Acc ording to this model, the field evolves in a well-behaved manner with no indication of instability or loss of equilibrium.