Possible method to improve the stability of twisted superconductors

The resistivity of the normal region between neighboring and opposite superconducting stripes/strands/filaments in twisted structures should be large enough to obtain the coupling losses at acceptable level. The stability of such structures can be then very low, as the individual superconductors are more or less electrically insulated. In such structures, any electromagnetic perturbations or spatial inhomogeneities can be detrimental for the conductor and eventually for the whole design. Concentrating mainly on helically wound striated coated conductors, we show that placing some normal sheets on the superconductor tapes without increasing the coupling losses considerably can enhance the electromagnetic coupling. The results may be extended also to similar superconducting structures with not very high coupling losses, but requiring better stability, because current sharing between superconducting parts is necessary for electromagnetic stability of longer conductors.