Distribution of Magnetic Field Inside the Winding of a BSCCO Coil

Due to strong magnetization currents induced in HTS coils wound with wide superconducting tapes the distribution of the magnetic field and currents inside the winding is difficult to calculate. We prepared an experimental coil wound with 4.2 mm wide multifilamentary BSCCO tape and measured the radial component of the magnetic field inside the winding using a thin Hall probe. At first, we calculated the radial component assuming a uniform current distribution and compared it with the data measured at room temperature. Then, the coil was cooled to 77 K and the evolution of the radial field distribution during the increase and decrease of the coil current was measured and compared with the calculations. The field map inside the winding is important for the calculation of AC losses, which are controlled by the radial field component.