Influence of High Frequency AC Magnetic Field on Trapped Magnetic Field

The trapped magnetic field in an HTS bulk is decayed and even erased by the application of an AC magnetic field whose amplitude is much smaller than the maximum trapped magnetic field. In previous experiments, the decay of the trapped magnetic field was shown to be due to the temperature rise of the bulk caused by the AC losses. Especially, in a high frequency magnetic field, AC losses are larger and the decay of the trapped magnetic field is accelerated by this AC loss increase. We investigated the time relationships of the AC loss of the HTS bulk in a high frequency magnetic field using the thermal equilibrium equation.