Design Process for a NbTi Wire With New Specification Objectives: Technical Design Constraints and Optimization of a Wire Layout Considering Critical Current and AC Losses

New ac applications set high requirements for the performance of superconductors. In particular, in particle accelerators, where large magnets are frequently charged and discharged, low ac losses and high stability must be provided. Otherwise, the cooling costs become intolerable, or the reliability cannot be guaranteed. Although the NbTi conductors have been available for a long time, new wire configurations are needed to fulfill new high performance requirements. Development work of a superconducting wire requires adjusting many parameters, such as filament size and zones and the composition of matrix metal. In addition, there are some technical limits for different design parameters due to the manufacturing process. In this paper, we consider the design process and the design parameters and their limitations from the manufacturer´s point of view. As a part of this NbTi wire design, the use of numerical ac loss computation and an optimization method is demonstrated in designing of a cross-section layout for minimizing the ac losses and to achieve a high critical current. This optimization method is among the first steps of numerical optimization procedures, which considers the geometrical optimization, and more studies are needed before it could become a method of practical use. However, in such a case, substantial savings in time and costs in a design process of a new wire can be achieved.