Magnetic behaviour of a superconducting hollow cylinder subjected to crossed fields: Experimental and modelling results

Experiments are carried out to study the decay of the axial magnetization of a hollow cylinder subjected to a transverse magnetic field varying with a low frequency (a “crossed-fields” configuration). The measured sample is a Bi-2223 cylinder immersed in a bath of liquid nitrogen (T = 77 K). The transverse field is applied with a sinusoidal or a triangular waveform and with a single or a double polarity. Flux-creep effects are subtracted from the magnetization decay. The magnetic induction at the centre of the cylinder is characterized as a function of time; the features of its decay are related to magnetic shielding measurements in either an axial or a transverse configuration. A numerical FEM model is performed on a hollow cylinder with a small aspect ratio to investigate the distribution of the superconducting currents as a function of time.