Current Distribution in the Winding of a Superconducting Coil

The current distribution in a HTS coil winding which uses a wide superconducting tape reflects the history of the current sourcing, the local inhomogeneity and especially the local distribution of the radial component of the magnetic field inside the winding. We measured the radial component of the magnetic field in a rectangular frame around the winding cross-section using a thin Hall probe. From the mapped data of radial component, the current distribution in the cross-section of the winding was determined using an inverse calculation relating the known mapped data and unknown distribution of the current's circumferential component in the coil. The Tikhonov method of regularization was applied in the calculation. The exact current distribution in the winding cross-section was approximated by a dense mesh of discrete points. The results are expressed for different coil currents during a gradual ramping up and down.