Magnetization And Ac Losses In Superconductors

Abstract Magnetization losses in superconducting filaments and other losses in superconductive wires, composites and cables in time-varying magnetic fields are of considerable importance to magnet design. Important theoretical and experimental investigations in this domain had been performed since the understanding of hard Type II superconductors due to the work of Bean and Kim (see chapter 2), Anderson et al. [1], which led to the development of the two main technical superconductors and and of other potential candidates, to be treated in Chapter 5.In the early 1970s high energy particle accelerators with superconductive dipole and quadrupole magnets and with duty cycles close to those of accelerators equipped with classical magnets were investigated; rise times of∼ 1 s and duty cycles of a few Hz had been assumed. Loss calculations have shown that such ‘fast’ cycled machines would require more elaborate composites and cables and higher performance cooling systems compared to quasi-de operated superconducting accelerators. It has been a fortunate coincidence that a parallel evolution pointed towards such an operation. Slow, long duration beam extraction and spilling techniques had been developed leading to cycles with longer flat tops of several minutes. When the advantages of particle colliders over fixed target machines became more and more evident [2,3,4] with flat tops extending to several hours or days, this mode of operation was also beneficial for the development of adequate superconducting de magnets.