THE EVOLUTION OF MAGNETIC-FIELDS AND PLASMAS IN OPEN-FIELD LINE CONFIGURATIONS

The nonideal behavior of the magnetic field is shown to depend only on the loop voltage, ∮E-dl, in open magnetic configurations. The tying of the plasma to the magnetic field is shown to be a weaker invariant than are the flux and helicity invariants that follow from the ideal form for the field evolution. The surfaces of constant loop voltages are shown to form a set of natural, or invariant, flux surfaces. These invariant flux surfaces are the equivalent in open geometries of the magnetic surfaces of toroidal geometry. © 1990 American Institute of Physics.