Recently, we have reported that screening currents in REBCO high field magnets may be a source of large electromagnetic stresses and consequently cause mechanical damage to the superconducting tape. To better estimate the electromechanical behavior of a REBCO magnet even in the initial design stage, we have modeled the distribution of screening currents in an NI REBCO magnet and compared the simulations with experiments to visualize the spatial distribution and temporal change of the screening currents within a REBCO sample tape. A 14 T, 161-mm low temperature superconductor background-field magnet, currently available at the Applied Superconductivity Center of the National High Magnetic Field Laboratory, is used to apply the magnetic field to induce screening currents in REBCO tapes. An array of calibrated Hall sensors is used to measure the time-varying magnetic fields on the REBCO tape’s surface. All tests are performed in a bath of liquid helium at 4.2 K.
This work was performed at the National High Magnetic Field Laboratory, which is supported by National Science Foundation Cooperative Agreement No. DMR-1644779 and DMR-1839796, and the State of Florida. A part of the analysis work by J. Bang and S. Hahn was supported by the National Research Foundation of Korea as a part of Mid-Career Research Program (No. 2018R1A2B3009249).