EFFECT OF SIZE ON LEVITATION FORCE IN A MAGNET SUPERCONDUCTOR SYSTEM/

We consider a model system consisting of an infinitely long magnetic d ipole line placed symmetrically above an infinitely long superconducti ng strip. Using the Meissner effect of superconductors, we derive anal ytical expressions of the levitation forces acting on the dipole line. At lowest-order approximation, we discuss the possible application of our model system to estimate the upper limit of the levitation forces in some magnetic bearing systems. In one example, the model correctly calculated the vertical vibration frequency of an experimental superc onducting bearing.