Investigation of long time constants of magnetic fields generated by the JT-60SA CS1 module

Loop currents with long time constants in CIC conductors have only been observed in large superconducting coils so far. To verify an occurrence of loop currents with long time constants in a CIC conductor without coil winding configuration, self-magnetic fields were measured using a short straight CIC conductor where a multi-strand cable was connected electrically at the conductor ends. As a result, loop currents with long time constants ranging from 57 s to 105 s occurred in the short straight CIC conductor, the length of which is approximately 1 m. The measurement results indicate that the conductor length is not always related to loop currents with long time constants. The occurrence of loop currents with long time constants in the CIC conductor depends on the presence of current paths at the conductor ends.