Estimation of temperature rise from trapped field gradient on superconducting bulk magnetized by multi-pulse technique

Trapped field profiles of the GdBaCuO superconducting bulk of 65 mm in diameter have been measured as magnetized using a successive pulsed-field application (SPA) and a subsequent iterative pulsed-field magnetization with reducing amplitude (IMRA). The trapped field gradient dBT/dx on the bulk periphery increases concomitantly with increasing pulse number in the IMRA part. The dBT/dx value on the bulk magnetized by field-cooled magnetization (FCM) was also measured at each temperature TF. The maximum temperature Tmax for each pulse was estimated by comparing the dBT/dx value for the IMRA part with that for the FCM at each temperature. Furthermore, Tmax was measured directly for the SPA part in the drilled hole in the bulk. The estimated Tmax was nearly equal to the measured Tmax, which thereby confirmed that Tmax after applying the pulsed field can be estimated using the dBT/dx value in the bulk periphery. The enhancement of the total trapped flux ΦTP in the IMRA part with increasing pulse number results from enhancement of the critical current density Jc because of the reduction in Tmax.