NONLOCAL CRITICAL-STATE MODEL FOR HARD SUPERCONDUCTORS

A new model describing the penetration of a magnetic field into hard superconductors is presented. It takes into account the nonlocal connection between the magnetic induction and the Abrikosov vortex density. The set of equations includes two independent relations for these variables. We have considered a new kind of barrier for the vortex penetration whose value is proportional to the critical current density. Our model permits to explain peculiarities of the AC absorption which we observed in a sample whose geometric characteristics are commensurable with the London penetration depth.