AC losses of coated conductors in perpendicular fields and concepts for twisting

AC losses for striped and unstriped YBCO coated conductors are presented. The loss for a sample subdivided into 10 filaments is shown to be reduced by the expected factor of 10. Various concepts for introducing strand twisting are investigated, and some estimates are given for their superconductive filling factors and the resulting twisting-induced strain. Additionally, the concept of winding induced effective twist is described, and the effective induced twist pitch is shown to be approximately two times the length of the winding. The influence of end-soldering of the strands is described, and simple estimates of the coupling losses are given for a striped strand with soldered ends in conjunction with an effective induced twist.