NUMERICAL EVALUATION OF MAGNETIC-LEVITATION FORCE FOR MAGNET-SUPERCONDUCTOR AXIAL SYMMETRY SYSTEMS

The magnetic interaction between a superconductor and a permanent magn et is analysed for a cylindrical system. Interaction force measurement s for several axial positions between Y-Ba-Cu-O melt textured pellets and permanent magnets with different dimensions are performed in zero field cooling or in field cooling conditions using a load cell system. For each configuration the interaction force is also numerically obta ined integrating the J x B term over the superconductor volume. In the frame of the Bean model the screening cm rent density into the superc onductor is kept constant at the critical value J(c). The current dist ribution into the superconducting material is considered to depend on the local magnetic field at the surface, which is evaluated by an iter ative calculation of the magnetic field generated by the current itsel f and by the permanent magnet. The free parameter J, utilised in the c alculations is evaluated by the remanent magnetic field profile mapped by a Hall sensor above the pellets surface. The model developed is su pported by a good agreement between numerical and experimental data.