A superconducting wire 20 with an electrically conductive core 2 in physical and electrical contact with a plurality of superconducting filaments 1 located around a periphery of the core which are partially exposed outside of the core over their length. The exposed filaments provide reduced power dissipation due to eddy currents, which also provides a resistance to quench events. An outer layer 3 may contact the filaments and have a resistivity of at least one hundred times the core 2. The materials of the core 2, filaments 1 and outer layer 3 may be Cu, NbTi and CuNi respectively. Alternatively the outer layer 3 may be made of a composite such as epoxy impregnated fibres. The filaments 1 may contact the core 2 over the majority of their circumference. The wire 20 may be used to form a coil for a magnet, used in an MRI (Magnetic Resonance Imaging) system.
