Question

What happens to magnetic $B$-field in a superconductor in the Bean model?

Answer 1

In the Bean model, as we start applying a magnetic field HH in the plane of a slab, the BB-field inside the superconductor decreases linearly from each side, and at a sufficiently high field H∗H∗ there is no longer anywhere in the superconductor where B=0B=0. What happens to the BB-field when H>H∗H>H∗? Diagrams that I've seen (such as the one in this answer) implies that the BB-field continues to increase as if the superconductor were now transparent to any additional field, but I'm confused. Shouldn't field that passes through a superconductor be quantized as vortices, and if so, shouldn't this increase the amount of trapped flux? Is my understanding that the superconductor in the Bean model doesn't react to any increased flux correct, and if so, is this an unphysical assumption that the Bean model makes?

Also, does the Bean model assume that an applied field has no effect on suppressing the superconductivity, so that Hc2Hc2 is meaningless in this model?

Answer 2

Explanation:

Bean's model predicted, and until now experiments confirmed, that to push as much magnetic field as possible into a superconductor.