  This paper describes a new and efficient method of defining an annular region
of a curl-free magnetic field with specific physics and coil properties that
can be used in stellarator design. Three statements define the importance: (1)
Codes can follow an optimized curl-free initial state to a final full-pressure
equilibrium. The large size of the optimization space of stellarators,
approximately fifty externally-produced distributions of magnetic field, makes
success in finding a global optimum largely determined by the starting point.
(2) The design of a stellarator is actually improved when the central region of
the plasma has rapid transport with the confinement provided by a surrounding
annulus of magnetic surfaces with low transport. (3) The stellarator is unique
among all fusion concepts, inertial as well as magnetic, in not using the
plasma itself to provide an essential part of its confinement concept. This
permits reliable computational design, which opens a path to faster, cheaper,
and more certain achievement of fusion energy.
