Composite Cu/Fe/MgB2 superconducting wires and MgB2/YSZ/Hastelloy coated conductors for ac and dc applications

We discuss the results of a study of MgB2 multifilamentary conductors and coated conductors from the point of view of their future dc and ac applications. The cot-relation between the slope of the irreversibility line induced by neutron irradiation defects and in situ structural imperfections and the critical temperature and critical current density is discussed with respect to the conductor performance and applicability. We debate the possible origin of the observed anomalous decrease of ac susceptibility at 50 K in copper clad in situ powder-in-tube MgB2 wires. Different conductor preparation methods and conductor architectures, and attainable critical current densities are presented. Some numerical results on critical currents, thermal stability and ac losses of future MgB2 multifilamentary and coated conductors with magnetic cladding of their filaments are also discussed.