A customized electric heater to mitigate screening current by optimal control on temperature distribution in a high-temperature superconductor coil

The so-called screening current in a high temperature superconductor (HTS) is a well-known phenomenon that has detrimental effects on performance of an HTS magnet. To date, many research efforts have been devoted to suppressing screening current in an HTS magnet. Here, we report a customized electric-heater, named “Thermal Eraser,” to mitigate the screening current. The key idea is to optimally control the spatial temperature distribution in an HTS magnet using the customized heater and the consequent temperature-dependent local critical current of HTS wires of the magnet. To validate the idea, a Thermal Eraser was designed, constructed, and installed in an actual single-pancake HTS coil. The Thermal Eraser with the test coil system was operated at temperatures ranging 7–40 K in our in-house conduction-cooling cryogenic facility. The feasibility of the Thermal Eraser was demonstrated in …