The high spatial homogeneity of critical current density, Jc, in HTS tape is one of the most important requirements to realize practical superconducting tapes. However, it is hardly possible to detect local Jc distribution using conventional characterization techniques because the length scale of such Jc variation is several orders smaller than that of the conventional techniques. We have succeeded in developing novel techniques such as low-temperature laser scanning microscopy and reel-toreel Hall probe scanning microscopy for spatially resolved measurements of local Jc in HTS tapes of multiple lengths and operating conditions. In this paper, I summarize these techniques together with other useful methods including magneto-optical imaging and the Hall sensor array technique.
Practical superconducting wires are designed with a composite structure to meet the desired engineering characteristics by expert selection of materials and design of the architecture. In practice, the local strain exerted on the superconducting component influences the electromagnetic properties. Here, recent progress in methods used to measure the local strain in practical superconducting wires and conductors using quantum beam techniques is introduced. Recent topics on the strain dependence of critical current are reviewed for three major practical wires: ITER-Nb3Sn strand, DI-BSCCO wires and REBCO tapes.