Magnetic flux density maps caused by DC, AC and remanence currents around artificial defects in Bi-2223/Ag tapes

The homogeneity of HTS tapes can be studied by measuring magnetic flux density maps with the Hall sensor magnetometer. The measurements are usually performed above samples carrying either the DC transport current or the remanence currents after switching off the transport current. In this paper time dependent maps above samples carrying AC transport current at 50 Hz are presented together with the DC and remanence maps. Several current amplitudes are used and measurements are repeated after drilling a hole into each sample. Finally, the applicability of the different types of maps to the homogeneity studies is discussed