In the present study, our emphasis was directed towards the fabrication process of long multi-core superconducting wires, each spanning several hundred meters. These wires feature an in situ MgB2 core, an ex situ MgB2 barrier, and a copper shield. The cost-effectiveness of these constituent materials, coupled with a judicious arrangement of internal components, facilitates the utilization of an economical shielding material for the resulting wire. Our ongoing efforts have successfully yielded several hundred-meter-long wire sections possessing favorable superconducting characteristics, making them suitable for self-field applications, such as direct current (DC) power lines.
Keywords: Cu shield; Cu-Ag rod; Cu-Ag wires; Mg diffusion; MgB2 powder; MgB2 wires; critical current density; ex situ MgB2 barrier; hydro-extrusion; long multi-core superconducting wires.