Superconducting toroidal magnets for fusion feasibility experiments and power reactors

It has been recognized that large superconducting magnets will have to be developed in order to obtain power economically from a thermonuclear reactor. In the present paper, we offer compelling reasons to illustrate how vital they are even for the sizes envisioned for hydrogen feasibility and D-T burning experiments. Detailed discussion is given on the type of magnets used for the plasma confinement in a tokamak-type machine. Illustrations are given to show that their development is within the present technological progress of superconductivity. The methods used to estimate the cost of such a toroidal system are provided along with how the cost varies with changes in magnet aspect ratio, major radius (varies as R$sup 1$.$sup 95$), and stored energy (varies as E$sup 0$.$sup 65$/sub s/). The latter quantity is presented as a valid figure of merit for quickly estimating the cost of any large superconducting toroidal system. (auth)