NONLOCAL CRITICAL-STATE MODEL FOR HARD SUPERCONDUCTORS

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