Superconducting Magnet Systems in Tokamak Engineering and Optimization

The aim of this paper is to study the interplay between plasma shaping and magnet systems in superconducting tokamaks. In particular, we study the optimization of the layout of the superconducting toroidal field (TF) coil system as a function of plasma elongation (kappa(xp)) and aspect ratio (A). By excluding the use of in-vessel control coils, we proceed by maximizing plasma elongation as a function of the aspect ratio to keep plasma operation safe with respect to vertical displacement events. In this respect, design criteria coming from tokamak operational experience as well as other designs are used as guidance. The layout of the superconducting magnet systems is then optimized to meet the key requirements of reference TF on the plasma axis and maximum TF ripple at the plasma boundary, volt-seconds availability, and plasma shaping while satisfying the constraints of conductor temperature margins, peak stresses in the TF coil central vault, and hoop stress in the central solenoid.