Abstract
In the united States and abroad there is intensive activity in thermonuclear research.1 A major part of this effort is directed toward containment, in strong magnetic fields, of plasma of the necessary high-particle energies, corresponding to temperatures of hundreds of millions of degrees Kelvin. Magnetic field design in thermonuclear research has already been developed to a relatively broad field of electrical engineering.2 The purpose of this paper is to discuss some theorems which are of special interest for the design of large d-c magnet coils as used, for instance, in the DCX (d-c experiment) thermonuclear research program of the Oak Ridge National Laboratory.3